requires VERSION_ES6 or -version 200 flag
Created by William Kapke and adapted for Rhino

# Rhino ES2015 Support

1.7R4 (these versions have identical results)
7% complete7% complete | 1.7R5 (these versions have identical results)
7% complete7% complete | 1.7.7.2 (these versions have identical results)
22% complete18% complete | 1.7.10 (these versions have identical results)
22% complete18% complete | 1.7.11 (these versions have identical results)
34% complete20% complete | 1.7.12 (these versions have identical results)
35% complete20% complete | 1.7.13 (these versions have identical results)
38% complete20% complete | 1.7.14 (these versions have identical results)
42% complete22% complete | 1.7.15 (these versions have identical results)
46% complete24% complete | 1.8.0 (these versions have identical results)
62% complete62% complete
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---

##
optimisation

### proper tail calls (tail call optimisation)
direct recursion ? function(){ "use strict"; return (function f(n){ if (n <= 0) { return "foo"; } return f(n - 1); }(1e6)) === "foo"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
mutual recursion ? function(){ "use strict"; function f(n){ if (n <= 0) { return "foo"; } return g(n - 1); } function g(n){ if (n <= 0) { return "bar"; } return f(n - 1); } return f(1e6) === "foo" && f(1e6+1) === "bar"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes

##
syntax

### default function parameters
basic functionality ? function(){ return (function (a = 1, b = 2) { return a === 3 && b === 2; }(3)); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
explicit undefined defers to the default ? function(){ return (function (a = 1, b = 2) { return a === 1 && b === 3; }(undefined, 3)); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
defaults can refer to previous params ? function(){ return (function (a, b = a) { return b === 5; }(5)); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
arguments object interaction ? function(){ return (function (a = "baz", b = "qux", c = "quux") { a = "corge"; // The arguments object is not mapped to the // parameters, even outside of strict mode. return arguments.length === 2 && arguments[0] === "foo" && arguments[1] === "bar"; }("foo", "bar")); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
temporal dead zone ? function(){ return (function(x = 1) { try { eval("(function(a=a){}())"); return false; } catch(e) {} try { eval("(function(a=b,b){}())"); return false; } catch(e) {} return true; }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
separate scope ? function(){ return (function(a=function(){ return typeof b === 'undefined'; }){ var b = 1; return a(); }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
new Function() support ? function(){ return new Function("a = 1", "b = 2", "return a === 3 && b === 2;" )(3); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### rest parameters
basic functionality ? function(){ return (function (foo, ...args) { return args instanceof Array && args + "" === "bar,baz"; }("foo", "bar", "baz")); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
function 'length' property ? function(){ return function(a, ...b){}.length === 1 && function(...c){}.length === 0; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
arguments object interaction ? function(){ return (function (foo, ...args) { foo = "qux"; // The arguments object is not mapped to the // parameters, even outside of strict mode. return arguments.length === 3 && arguments[0] === "foo" && arguments[1] === "bar" && arguments[2] === "baz"; }("foo", "bar", "baz")); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No
can't be used in setters ? function(){ return (function (...args) { try { eval("({set e(...args){}})"); } catch(e) { return true; } }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No
new Function() support ? function(){ return new Function("a", "...b", "return b instanceof Array && a+b === 'foobar,baz';" )('foo','bar','baz'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
### spread syntax for iterable objects
with arrays, in function calls ? function(){ return Math.max(...[1, 2, 3]) === 3 } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with arrays, in array literals ? function(){ return [...[1, 2, 3]][2] === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with sparse arrays, in function calls ? function(){ var a = Array(...[,,]); return "0" in a && "1" in a && '' + a[0] + a[1] === "undefinedundefined"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with sparse arrays, in array literals ? function(){ var a = [...[,,]]; return "0" in a && "1" in a && '' + a[0] + a[1] === "undefinedundefined"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with strings, in function calls ? function(){ return Math.max(..."1234") === 4; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with strings, in array literals ? function(){ return ["a", ..."bcd", "e"][3] === "d"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with astral plane strings, in function calls ? function(){ return Array(..."𠮷𠮶")[0] === "𠮷"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with astral plane strings, in array literals ? function(){ return [..."𠮷𠮶"][0] === "𠮷"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with generator instances, in calls ? function(){ var iterable = (function*(){ yield 1; yield 2; yield 3; }()); return Math.max(...iterable) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with generator instances, in arrays ? function(){ var iterable = (function*(){ yield "b"; yield "c"; yield "d"; }()); return ["a", ...iterable, "e"][3] === "d"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with generic iterables, in calls ? function(){ var iterable = global.__createIterableObject([1, 2, 3]); return Math.max(...iterable) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with generic iterables, in arrays ? function(){ var iterable = global.__createIterableObject(["b", "c", "d"]); return ["a", ...iterable, "e"][3] === "d"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with instances of iterables, in calls ? function(){ var iterable = global.__createIterableObject([1, 2, 3]); return Math.max(...Object.create(iterable)) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
with instances of iterables, in arrays ? function(){ var iterable = global.__createIterableObject(["b", "c", "d"]); return ["a", ...Object.create(iterable), "e"][3] === "d"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
spreading non-iterables is a runtime error ? function(){ try { Math.max(...2); } catch(e) { return Math.max(...[1, 2, 3]) === 3; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### object literal extensions
computed properties ? function(){ var x = 'y'; return ({ [x]: 1 }).y === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
shorthand properties ? function(){ var a = 7, b = 8, c = {a,b}; return c.a === 7 && c.b === 8; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
shorthand methods ? function(){ return ({ y() { return 2; } }).y() === 2; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
string-keyed shorthand methods ? function(){ return ({ "foo bar"() { return 4; } })["foo bar"]() === 4; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
computed shorthand methods ? function(){ var x = 'y'; return ({ [x](){ return 1 } }).y() === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
computed accessors ? function(){ var x = 'y', valueSet, obj = { get [x] () { return 1 }, set [x] (value) { valueSet = value } }; obj.y = 'foo'; return obj.y === 1 && valueSet === 'foo'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### for..of loops
with arrays ? function(){ var arr = [5]; for (var item of arr) return item === 5; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
with sparse arrays ? function(){ var arr = [,,]; var count = 0; for (var item of arr) count += (item === void undefined); return count === 2; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
with strings ? function(){ var str = ""; for (var item of "foo") str += item; return str === "foo"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
with astral plane strings ? function(){ var str = ""; for (var item of "𠮷𠮶") str += item + " "; return str === "𠮷 𠮶 "; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
with generator instances ? function(){ var result = ""; var iterable = (function*(){ yield 1; yield 2; yield 3; }()); for (var item of iterable) { result += item; } return result === "123"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
with generic iterables ? function(){ var result = ""; var iterable = global.__createIterableObject([1, 2, 3]); for (var item of iterable) { result += item; } return result === "123"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
with instances of generic iterables ? function(){ var result = ""; var iterable = global.__createIterableObject([1, 2, 3]); for (var item of Object.create(iterable)) { result += item; } return result === "123"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
iterator closing, break ? function(){ var closed = false; var iter = __createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); for (var it of iter) break; return closed; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
iterator closing, throw ? function(){ var closed = false; var iter = __createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); try { for (var it of iter) throw 0; } catch(e){} return closed; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
### octal and binary literals
octal literals ? function(){ return 0o10 === 8 && 0O10 === 8; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
binary literals ? function(){ return 0b10 === 2 && 0B10 === 2; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
octal supported by Number() ? function(){ return Number('0o1') === 1; } | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
binary supported by Number() ? function(){ return Number('0b1') === 1; } | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
### template literals
basic functionality ? function(){ var a = "ba", b = "QUX"; return `foo bar ${a + "z"} ${b.toLowerCase()}` === "foo bar\nbaz qux"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
toString conversion ? function(){ var a = { toString: function() { return "foo"; }, valueOf: function() { return "bar"; } }; return `${a}` === "foo"; } | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | No No | No No | No No
tagged template literals ? function(){ var called = false; function fn(parts, a, b) { called = true; return parts instanceof Array && parts[0] === "foo" && parts[1] === "bar\n" && parts.raw[0] === "foo" && parts.raw[1] === "bar\\n" && a === 123 && b === 456; } return fn `foo${123}bar\n${456}` && called; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
passed array is frozen ? function(){ return (function(parts) { return Object.isFrozen(parts) && Object.isFrozen(parts.raw); }) `foo${0}bar${0}baz`; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
line break normalisation ? function(){ var cr = eval("`x" + String.fromCharCode(13) + "y`"); var lf = eval("`x" + String.fromCharCode(10) + "y`"); var crlf = eval("`x" + String.fromCharCode(13,10) + "y`"); return cr.length === 3 && lf.length === 3 && crlf.length === 3 && cr[1] === lf[1] && lf[1] === crlf[1] && crlf[1] === '\n'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
TemplateStrings call site caching ? function(){ // TemplateStrings caching was changed from per-contents to // per-call-site. // https://github.com/tc39/ecma262/pull/890 function strings(array) { return array; } function getStrings() { return strings`foo`; } var original = getStrings(); var other = strings`foo`; return original === getStrings() && original !== other; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
TemplateStrings permanent caching ? function(){ function strings(array) { return array; } function getStrings() { return strings`foo`; } var original = getStrings(); var newed = new getStrings(); return original === getStrings() && original === newed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes
### RegExp "y" and "u" flags
"y" flag ? function(){ var re = new RegExp('\\w', 'y'); re.exec('xy'); return (re.exec('xy')[0] === 'y'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
"y" flag, lastIndex ? function(){ var re = new RegExp('yy', 'y'); re.lastIndex = 3; var result = re.exec('xxxyyxx')[0]; return result === 'yy' && re.lastIndex === 5; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
"u" flag ? function(){ return "𠮷".match(/^.$/u)[0].length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
"u" flag, non-BMP Unicode characters ? function(){ return "𠮷x".match(/^.x$/u)[0].length === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
"u" flag, Unicode code point escapes ? function(){ return "𝌆".match(/\u{1d306}/u)[0].length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
"u" flag, case folding ? function(){ return "ſ".match(/S/iu) && "S".match(/ſ/iu); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### destructuring, declarations
with arrays ? function(){ var [a, , [b], c] = [5, null, [6]]; return a === 5 && b === 6 && c === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with sparse arrays ? function(){ var [a, , b] = [,,,]; return a === void undefined && b === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with strings ? function(){ var [a, b, c] = "ab"; return a === "a" && b === "b" && c === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with astral plane strings ? function(){ var [c] = "𠮷𠮶"; return c === "𠮷"; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with generator instances ? function(){ var [a, b, c] = (function*(){ yield 1; yield 2; }()); return a === 1 && b === 2 && c === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | No No
with generic iterables ? function(){ var [a, b, c] = global.__createIterableObject([1, 2]); return a === 1 && b === 2 && c === void undefined; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with instances of generic iterables ? function(){ var [a, b, c] = Object.create(global.__createIterableObject([1, 2])); return a === 1 && b === 2 && c === void undefined; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); var [a, b] = iter; return closed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
trailing commas in iterable patterns ? function(){ var [a,] = [1]; return a === 1; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with objects ? function(){ var {c, x:d, e} = {c:7, x:8}; return c === 7 && d === 8 && e === void undefined; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
object destructuring with primitives ? function(){ var {toFixed} = 2; var {slice} = ''; return toFixed === Number.prototype.toFixed && slice === String.prototype.slice; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
trailing commas in object patterns ? function(){ var {a,} = {a:1}; return a === 1; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
throws on null and undefined ? function(){ try { var {a} = null; return false; } catch(e) { if (!(e instanceof TypeError)) return false; } try { var {b} = void undefined; return false; } catch(e) { if (!(e instanceof TypeError)) return false; } return true; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
computed properties ? function(){ var qux = "corge"; var { [qux]: grault } = { corge: "garply" }; return grault === "garply"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
multiples in a single var statement ? function(){ var [a,b] = [5,6], {c,d} = {c:7,d:8}; return a === 5 && b === 6 && c === 7 && d === 8; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
nested ? function(){ var [e, {x:f, g}] = [9, {x:10}]; var {h, x:[i]} = {h:11, x:[12]}; return e === 9 && f === 10 && g === void undefined && h === 11 && i === 12; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
in for-in loop heads ? function(){ for(var [i, j, k] in { qux: 1 }) { return i === "q" && j === "u" && k === "x"; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
in for-of loop heads ? function(){ for(var [i, j, k] of [[1,2,3]]) { return i === 1 && j === 2 && k === 3; } } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
in catch heads ? function(){ try { throw [1,2]; } catch([i,j]) { try { throw { k: 3, l: 4 }; } catch({k, l}) { return i === 1 && j === 2 && k === 3 && l === 4; } } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
rest ? function(){ var [a, ...b] = [3, 4, 5]; var [c, ...d] = [6]; return a === 3 && b instanceof Array && (b + "") === "4,5" && c === 6 && d instanceof Array && d.length === 0; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
defaults ? function(){ var {a = 1, b = 0, z:c = 3} = {b:2, z:undefined}; var [d = 0, e = 5, f = 6] = [4,,undefined]; return a === 1 && b === 2 && c === 3 && d === 4 && e === 5 && f === 6; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
defaults, let temporal dead zone ? function(){ var {a, b = 2} = {a:1}; try { eval("let {c = c} = {};"); return false; } catch(e){} try { eval("let {c = d, d} = {d:1};"); return false; } catch(e){} return a === 1 && b === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### destructuring, assignment
with arrays ? function(){ var a,b,c; [a, , [b], c] = [5, null, [6]]; return a === 5 && b === 6 && c === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with sparse arrays ? function(){ var a, b; [a, , b] = [,,,]; return a === void undefined && b === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with strings ? function(){ var a,b,c; [a, b, c] = "ab"; return a === "a" && b === "b" && c === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with astral plane strings ? function(){ var c; [c] = "𠮷𠮶"; return c === "𠮷"; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with generator instances ? function(){ var a,b,c; [a, b, c] = (function*(){ yield 1; yield 2; }()); return a === 1 && b === 2 && c === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | No No
with generic iterables ? function(){ var a,b,c; [a, b, c] = global.__createIterableObject([1, 2]); return a === 1 && b === 2 && c === void undefined; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with instances of generic iterables ? function(){ var a,b,c; [a, b, c] = Object.create(global.__createIterableObject([1, 2])); return a === 1 && b === 2 && c === void undefined; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); var a,b; [a, b] = iter; return closed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
iterable destructuring expression ? function(){ var a, b, iterable = [1,2]; return ([a, b] = iterable) === iterable; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
chained iterable destructuring ? function(){ var a,b,c,d; [a,b] = [c,d] = [1,2]; return a === 1 && b === 2 && c === 1 && d === 2; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
trailing commas in iterable patterns ? function(){ var a; [a,] = [1]; return a === 1; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with objects ? function(){ var c,d,e; ({c, x:d, e} = {c:7, x:8}); return c === 7 && d === 8 && e === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
object destructuring with primitives ? function(){ var toFixed, slice; ({toFixed} = 2); ({slice} = ''); return toFixed === Number.prototype.toFixed && slice === String.prototype.slice; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
trailing commas in object patterns ? function(){ var a; ({a,} = {a:1}); return a === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
object destructuring expression ? function(){ var a, b, obj = { a:1, b:2 }; return ({a,b} = obj) === obj; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
parenthesised left-hand-side is a syntax error ? function(){ var a, b; ({a,b} = {a:1,b:2}); try { eval("({a,b}) = {a:3,b:4};"); } catch(e) { return a === 1 && b === 2; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | No No
chained object destructuring ? function(){ var a,b,c,d; ({a,b} = {c,d} = {a:1,b:2,c:3,d:4}); return a === 1 && b === 2 && c === 3 && d === 4; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
throws on null and undefined ? function(){ var a,b; try { ({a} = null); return false; } catch(e) { if (!(e instanceof TypeError)) return false; } try { ({b} = void undefined); return false; } catch(e) { if (!(e instanceof TypeError)) return false; } return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
computed properties ? function(){ var grault, qux = "corge"; ({ [qux]: grault } = { corge: "garply" }); return grault === "garply"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
nested ? function(){ var e,f,g,h,i; [e, {x:f, g}] = [9, {x:10}]; ({h, x:[i]} = {h:11, x:[12]}); return e === 9 && f === 10 && g === void undefined && h === 11 && i === 12; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
rest ? function(){ var a,b,c,d; [a, ...b] = [3, 4, 5]; [c, ...d] = [6]; return a === 3 && b instanceof Array && (b + "") === "4,5" && c === 6 && d instanceof Array && d.length === 0; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
nested rest ? function(){ var a = [1, 2, 3], first, last; [first, ...[a[2], last]] = a; return first === 1 && last === 3 && (a + "") === "1,2,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
empty patterns ? function(){ [] = [1,2]; ({} = {a:1,b:2}); return true; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
defaults ? function(){ var a,b,c,d,e,f; ({a = 1, b = 0, z:c = 3} = {b:2, z:undefined}); [d = 0, e = 5, f = 6] = [4,,undefined]; return a === 1 && b === 2 && c === 3 && d === 4 && e === 5 && f === 6; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### destructuring, parameters
with arrays ? function(){ return function([a, , [b], c]) { return a === 5 && b === 6 && c === void undefined; }([5, null, [6]]); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with sparse arrays ? function(){ return function([a, , b]) { return a === void undefined && b === void undefined; }([,,,]); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with strings ? function(){ return function([a, b, c]) { return a === "a" && b === "b" && c === void undefined; }("ab"); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with astral plane strings ? function(){ return function([c]) { return c === "𠮷"; }("𠮷𠮶"); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with generator instances ? function(){ return function([a, b, c]) { return a === 1 && b === 2 && c === void undefined; }(function*(){ yield 1; yield 2; }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | No No
with generic iterables ? function(){ return function([a, b, c]) { return a === 1 && b === 2 && c === void undefined; }(global.__createIterableObject([1, 2])); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
with instances of generic iterables ? function(){ return function([a, b, c]) { return a === 1 && b === 2 && c === void undefined; }(Object.create(global.__createIterableObject([1, 2]))); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); (function([a,b]) {}(iter)); return closed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
trailing commas in iterable patterns ? function(){ return function([a,]) { return a === 1; }([1]); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
with objects ? function(){ return function({c, x:d, e}) { return c === 7 && d === 8 && e === void undefined; }({c:7, x:8}); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
object destructuring with primitives ? function(){ return function({toFixed}, {slice}) { return toFixed === Number.prototype.toFixed && slice === String.prototype.slice; }(2,''); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
trailing commas in object patterns ? function(){ return function({a,}) { return a === 1; }({a:1}); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
throws on null and undefined ? function(){ try { (function({a}){}(null)); return false; } catch(e) {} try { (function({b}){}(undefined)); return false; } catch(e) {} return true; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
computed properties ? function(){ var qux = "corge"; return function({ [qux]: grault }) { return grault === "garply"; }({ corge: "garply" }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
nested ? function(){ return function([e, {x:f, g}], {h, x:[i]}) { return e === 9 && f === 10 && g === void undefined && h === 11 && i === 12; }([9, {x:10}],{h:11, x:[12]}); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
'arguments' interaction ? function(){ return (function({a, x:b, y:e}, [c, d]) { return arguments[0].a === 1 && arguments[0].x === 2 && !("y" in arguments[0]) && arguments[1] + '' === "3,4"; }({a:1, x:2}, [3, 4])); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
new Function() support ? function(){ return new Function("{a, x:b, y:e}","[c, d]", "return a === 1 && b === 2 && c === 3 && " + "d === 4 && e === void undefined;" )({a:1, x:2}, [3, 4]); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
in parameters, function 'length' property ? function(){ return function({a, b}, [c, d]){}.length === 2; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
rest ? function(){ return function([a, ...b], [c, ...d]) { return a === 3 && b instanceof Array && (b + "") === "4,5" && c === 6 && d instanceof Array && d.length === 0; }([3, 4, 5], [6]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
empty patterns ? function(){ return function ([],{}){ return arguments[0] + '' === "3,4" && arguments[1].x === "foo"; }([3,4],{x:"foo"}); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
defaults ? function(){ return (function({a = 1, b = 0, c = 3, x:d = 0, y:e = 5}, [f = 6, g = 0, h = 8]) { return a === 1 && b === 2 && c === 3 && d === 4 && e === 5 && f === 6 && g === 7 && h === 8; }({b:2, c:undefined, x:4},[, 7, undefined])); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
defaults, separate scope ? function(){ return (function({a=function(){ return typeof b === 'undefined'; }}){ var b = 1; return a(); }({})); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
defaults, new Function() support ? function(){ return new Function("{a = 1, b = 0, c = 3, x:d = 0, y:e = 5}", "return a === 1 && b === 2 && c === 3 && d === 4 && e === 5;" )({b:2, c:undefined, x:4}); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
aliased defaults, arrow function ? function(){ return ((a, {b: x = 0, c: y = 3}) => { return a === 1 && x === 2 && y === 3; })(1, {b: 2}); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
shorthand defaults, arrow function ? function(){ return ((a, {b = 0, c = 3}) => { return a === 1 && b === 2 && c === 3; })(1, {b: 2}); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
duplicate identifier ? function(){ try { eval('var d = function d([d]) { return d };'); if (d([true]) !== true) return false; } catch (e) { return !(e instanceof SyntaxError); } try { eval('var f = function f([id, id]) { return id }'); return false; } catch (e) { return e instanceof SyntaxError; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
### Unicode code point escapes
in strings ? function(){ return '\u{1d306}' === '\ud834\udf06'; } | No No | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes
in identifiers ? function(){ var \u{102C0} = 2; return \u{102C0} === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
in property key definitions ? function(){ var o = { \u{102C0} : 2 }; return o['\ud800\udec0'] === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
in property key accesses ? function(){ var o = { '\ud800\udec0' : 2 }; return o.\u{102C0} === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
### new.target
in constructors ? function(){ var passed = false; new function f() { passed = (new.target === f); }(); (function() { passed &= (new.target === void undefined); }()); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
assignment is an early error ? function(){ var passed = false; new function f() { passed = (new.target === f); }(); try { Function("new.target = function(){};"); } catch(e) { return passed; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
bindings

### const
basic support ? function(){ const foo = 123; return (foo === 123); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
is block-scoped ? function(){ const bar = 123; { const bar = 456; } return bar === 123; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
scope shadow resolution ? function(){ try { { const bar = 456; } const bar = 123; return bar === 123; } catch(e) { return false; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
cannot be in statements ? function(){ const bar = 1; try { Function("if(true) const baz = 1;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
redefining a const is an error ? function(){ const baz = 1; try { Function("const foo = 1; foo = 2;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for loop statement scope ? function(){ const baz = 1; for(const baz = 0; false;) {} return baz === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
for-in loop iteration scope ? function(){ var scopes = []; for(const i in { a:1, b:1 }) { scopes.push(function(){ return i; }); } return (scopes[0]() === "a" && scopes[1]() === "b"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
for-of loop iteration scope ? function(){ var scopes = []; for(const i of ['a','b']) { scopes.push(function(){ return i; }); } return (scopes[0]() === "a" && scopes[1]() === "b"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
temporal dead zone ? function(){ var passed = (function(){ try { qux; } catch(e) { return true; }}()); function fn() { passed &= qux === 456; } const qux = 456; fn(); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
basic support (strict mode) ? function(){ "use strict"; const foo = 123; return (foo === 123); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
is block-scoped (strict mode) ? function(){ 'use strict'; const bar = 123; { const bar = 456; } return bar === 123; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
scope shadow resolution (strict mode) ? function(){ 'use strict'; try { { const bar = 456; } const bar = 123; return bar === 123; } catch(e) { return false; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
cannot be in statements (strict mode) ? function(){ 'use strict'; const bar = 1; try { Function("'use strict'; if(true) const baz = 1;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
redefining a const (strict mode) ? function(){ 'use strict'; const baz = 1; try { Function("'use strict'; const foo = 1; foo = 2;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for loop statement scope (strict mode) ? function(){ 'use strict'; const baz = 1; for(const baz = 0; false;) {} return baz === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
for-in loop iteration scope (strict mode) ? function(){ 'use strict'; var scopes = []; for(const i in { a:1, b:1 }) { scopes.push(function(){ return i; }); } return (scopes[0]() === "a" && scopes[1]() === "b"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
for-of loop iteration scope (strict mode) ? function(){ 'use strict'; var scopes = []; for(const i of ['a','b']) { scopes.push(function(){ return i; }); } return (scopes[0]() === "a" && scopes[1]() === "b"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
temporal dead zone (strict mode) ? function(){ 'use strict'; var passed = (function(){ try { qux; } catch(e) { return true; }}()); function fn() { passed &= qux === 456; } const qux = 456; fn(); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
### let
basic support ? function(){ let foo = 123; return (foo === 123); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
is block-scoped ? function(){ let bar = 123; { let bar = 456; } return bar === 123; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
scope shadow resolution ? function(){ try { { let bar = 456; } let bar = 123; return bar === 123; } catch(e) { return false; } } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
cannot be in statements ? function(){ let bar = 1; try { Function("if(true) let baz = 1;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for loop statement scope ? function(){ let baz = 1; for(let baz = 0; false;) {} return baz === 1; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
temporal dead zone ? function(){ var passed = (function(){ try { qux; } catch(e) { return true; }}()); function fn() { passed &= qux === 456; } let qux = 456; fn(); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for/for-in loop iteration scope ? function(){ let scopes = []; for(let i = 0; i < 2; i++) { scopes.push(function(){ return i; }); } let passed = (scopes[0]() === 0 && scopes[1]() === 1); scopes = []; for(let i in { a:1, b:1 }) { scopes.push(function(){ return i; }); } passed &= (scopes[0]() === "a" && scopes[1]() === "b"); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for-in loop binding shadowing parameter ? function(){ try { Function("function f(e) { for (let e in {}) e }"); return true; } catch(e) { return false; } } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
basic support (strict mode) ? function(){ 'use strict'; let foo = 123; return (foo === 123); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
is block-scoped (strict mode) ? function(){ 'use strict'; let bar = 123; { let bar = 456; } return bar === 123; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
scope shadow resolution (strict mode) ? function(){ 'use strict'; try { { let bar = 456; } let bar = 123; return bar === 123; } catch(e) { return false; } } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
cannot be in statements (strict mode) ? function(){ 'use strict'; let bar = 1; try { Function("'use strict'; if(true) let baz = 1;")(); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for loop statement scope (strict mode) ? function(){ 'use strict'; let baz = 1; for(let baz = 0; false;) {} return baz === 1; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
temporal dead zone (strict mode) ? function(){ 'use strict'; var passed = (function(){ try { qux; } catch(e) { return true; }}()); function fn() { passed &= qux === 456; } let qux = 456; fn(); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for/for-in loop iteration scope (strict mode) ? function(){ 'use strict'; let scopes = []; for(let i = 0; i < 2; i++) { scopes.push(function(){ return i; }); } let passed = (scopes[0]() === 0 && scopes[1]() === 1); scopes = []; for(let i in { a:1, b:1 }) { scopes.push(function(){ return i; }); } passed &= (scopes[0]() === "a" && scopes[1]() === "b"); return passed; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
for-in loop binding shadowing parameter (strict mode) ? function(){ try { Function("'use strict'; function f(e) { for (let e in {}) e }"); return true; } catch(e) { return false; } } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
###
block-level function declaration ? function(){ 'use strict'; if (f() !== 1) return false; function f() { return 1; } { if (f() !== 2) return false; function f() { return 2; } if (f() !== 2) return false; } if (f() !== 1) return false; return true; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No

##
functions

### arrow functions
0 parameters ? function(){ return (() => 5)() === 5; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
1 parameter, no brackets ? function(){ var b = x => x + "foo"; return (b("fee fie foe ") === "fee fie foe foo"); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
multiple parameters ? function(){ var c = (v, w, x, y, z) => "" + v + w + x + y + z; return (c(6, 5, 4, 3, 2) === "65432"); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
lexical "this" binding ? function(){ var d = { x : "bar", y : function() { return z => this.x + z; }}.y(); var e = { x : "baz", y : d }; return d("ley") === "barley" && e.y("ley") === "barley"; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
"this" unchanged by call or apply ? function(){ var d = { x : "foo", y : function() { return () => this.x; }}; var e = { x : "bar" }; return d.y().call(e) === "foo" && d.y().apply(e) === "foo"; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
can't be bound, can be curried ? function(){ var d = { x : "bar", y : function() { return z => this.x + z; }}; var e = { x : "baz" }; return d.y().bind(e, "ley")() === "barley"; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
lexical "arguments" binding ? function(){ var f = (function() { return z => arguments[0]; }(5)); return f(6) === 5; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
no line break between params and => ? function(){ return (() => { try { Function("x\n => 2")(); } catch(e) { return true; } })(); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
correct precedence ? function(){ return (() => { try { Function("0 || () => 2")(); } catch(e) { return true; } })(); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
no "prototype" property ? function(){ var a = () => 5; return !a.hasOwnProperty("prototype"); } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
lexical "super" binding in constructors ? function(){ var received; class B { constructor (arg) { received = arg; } } class C extends B { constructor () { var callSuper = () => super('foo'); callSuper(); } } return new C instanceof C && received === 'foo' } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
lexical "super" binding in methods ? function(){ class B { qux() { return "quux"; } } class C extends B { baz() { return x => super.qux(); } } var arrow = new C().baz(); return arrow() === "quux"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
lexical "new.target" binding ? function(){ function C() { return x => new.target; } return new C()() === C && C()() === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### class
class statement ? function(){ class C {} return typeof C === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
is block-scoped ? function(){ class C {} var c1 = C; { class C {} var c2 = C; } return C === c1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
class expression ? function(){ return typeof class C {} === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
anonymous class ? function(){ return typeof class {} === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
constructor ? function(){ class C { constructor() { this.x = 1; } } return C.prototype.constructor === C && new C().x === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
prototype methods ? function(){ class C { method() { return 2; } } return typeof C.prototype.method === "function" && new C().method() === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
string-keyed methods ? function(){ class C { "foo bar"() { return 2; } } return typeof C.prototype["foo bar"] === "function" && new C()["foo bar"]() === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed prototype methods ? function(){ var foo = "method"; class C { [foo]() { return 2; } } return typeof C.prototype.method === "function" && new C().method() === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
optional semicolons ? function(){ class C { ; method() { return 2; }; method2() { return 2; } method3() { return 2; }; } return typeof C.prototype.method === "function" && typeof C.prototype.method2 === "function" && typeof C.prototype.method3 === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
static methods ? function(){ class C { static method() { return 3; } } return typeof C.method === "function" && C.method() === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed static methods ? function(){ var foo = "method"; class C { static [foo]() { return 3; } } return typeof C.method === "function" && C.method() === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
accessor properties ? function(){ var baz = false; class C { get foo() { return "foo"; } set bar(x) { baz = x; } } new C().bar = true; return new C().foo === "foo" && baz; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed accessor properties ? function(){ var garply = "foo", grault = "bar", baz = false; class C { get [garply]() { return "foo"; } set [grault](x) { baz = x; } } new C().bar = true; return new C().foo === "foo" && baz; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
static accessor properties ? function(){ var baz = false; class C { static get foo() { return "foo"; } static set bar(x) { baz = x; } } C.bar = true; return C.foo === "foo" && baz; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed static accessor properties ? function(){ var garply = "foo", grault = "bar", baz = false; class C { static get [garply]() { return "foo"; } static set [grault](x) { baz = x; } } C.bar = true; return C.foo === "foo" && baz; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
class name is lexically scoped ? function(){ class C { method() { return typeof C === "function"; } } var M = C.prototype.method; C = void undefined; return C === void undefined && M(); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed names, temporal dead zone ? function(){ try { var B = class C { [C](){} } } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
methods aren't enumerable ? function(){ class C { foo() {} static bar() {} } return !C.prototype.propertyIsEnumerable("foo") && !C.propertyIsEnumerable("bar"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
implicit strict mode ? function(){ class C { static method() { return this === void undefined; } } return (0,C.method)(); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
constructor requires new ? function(){ class C {} try { C(); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
extends ? function(){ class B {} class C extends B {} return new C() instanceof B && B.isPrototypeOf(C); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
extends expressions ? function(){ var B; class C extends (B = class {}) {} return new C() instanceof B && B.isPrototypeOf(C); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
extends null ? function(){ class C extends null { constructor() { return Object.create(null); } } return Function.prototype.isPrototypeOf(C) && Object.getPrototypeOf(C.prototype) === null; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
new.target ? function(){ var passed = false; new function f() { passed = new.target === f; }(); class A { constructor() { passed &= new.target === B; } } class B extends A {} new B(); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### super
statement in constructors ? function(){ var passed = false; class B { constructor(a) { passed = (a === "barbaz"); } } class C extends B { constructor(a) { super("bar" + a); } } new C("baz"); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
expression in constructors ? function(){ class B { constructor(a) { return ["foo" + a]; } } class C extends B { constructor(a) { return super("bar" + a); } } return new C("baz")[0] === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
in methods, property access ? function(){ class B {} B.prototype.qux = "foo"; B.prototype.corge = "baz"; class C extends B { quux(a) { return super.qux + a + super["corge"]; } } C.prototype.qux = "garply"; return new C().quux("bar") === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
in methods, method calls ? function(){ class B { qux(a) { return "foo" + a; } } class C extends B { qux(a) { return super.qux("bar" + a); } } return new C().qux("baz") === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
method calls use correct "this" binding ? function(){ class B { qux(a) { return this.foo + a; } } class C extends B { qux(a) { return super.qux("bar" + a); } } var obj = new C(); obj.foo = "foo"; return obj.qux("baz") === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
constructor calls use correct "new.target" binding ? function(){ var passed; class B { constructor() { passed = (new.target === C); } } class C extends B { constructor() { super(); } } new C(); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
is statically bound ? function(){ class B { qux() { return "bar"; } } class C extends B { qux() { return super.qux() + this.corge; } } var obj = { qux: C.prototype.qux, corge: "ley" }; return obj.qux() === "barley"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
super() invokes the correct constructor ? function(){ // checks that super() is *not* a synonym of super.constructor() var passed; class B { constructor() { passed = true; } }; B.prototype.constructor = function () { passed = false; }; class C extends B { }; new C; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### generators
basic functionality ? function(){ function * generator(){ yield 5; yield 6; }; var iterator = generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
generator function expressions ? function(){ var generator = function * (){ yield 5; yield 6; }; var iterator = generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No Flag | No Flag | No Flag | Yes Yes
correct "this" binding ? function(){ function * generator(){ yield this.x; yield this.y; }; var iterator = { g: generator, x: 5, y: 6 }.g(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
can't use "this" with new ? function(){ function * generator(){ yield this.x; yield this.y; }; try { (new generator()).next(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | No No
sending ? function(){ var sent; function * generator(){ sent = [yield 5, yield 6]; }; var iterator = generator(); iterator.next(); iterator.next("foo"); iterator.next("bar"); return sent[0] === "foo" && sent[1] === "bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
%GeneratorPrototype% ? function(){ function * generatorFn(){} var ownProto = Object.getPrototypeOf(generatorFn()); var passed = ownProto === generatorFn.prototype; var sharedProto = Object.getPrototypeOf(ownProto); passed &= sharedProto !== Object.prototype && sharedProto === Object.getPrototypeOf(function*(){}.prototype) && sharedProto.hasOwnProperty('next'); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | No No
%GeneratorPrototype% prototype chain ? function(){ function * generatorFn(){} var g = generatorFn(); var ownProto = Object.getPrototypeOf(g); var passed = ownProto === generatorFn.prototype; var sharedProto = Object.getPrototypeOf(ownProto); var iterProto = Object.getPrototypeOf(sharedProto); passed &= iterProto.hasOwnProperty(Symbol.iterator) && !sharedProto .hasOwnProperty(Symbol.iterator) && !ownProto .hasOwnProperty(Symbol.iterator) && g[Symbol.iterator]() === g; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
%GeneratorPrototype%.constructor ? function(){ function * g (){} var iterator = new g.constructor("a","b","c","yield a; yield b; yield c;")(5,6,7); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === 7 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; passed &= g.constructor === (function*(){}).constructor; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
%GeneratorPrototype%.throw ? function(){ var passed = false; function * generator(){ try { yield 5; yield 6; } catch(e) { passed = (e === "foo"); } }; var iterator = generator(); iterator.next(); iterator.throw("foo"); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
%GeneratorPrototype%.return ? function(){ function * generator(){ yield 5; yield 6; }; var iterator = generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.return("quxquux"); passed &= item.value === "quxquux" && item.done === true; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | No No
yield operator precedence ? function(){ var passed; function * generator(){ passed = yield 0 ? true : false; }; var iterator = generator(); iterator.next(); iterator.next(true); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, arrays ? function(){ var iterator = (function * generator() { yield * [5, 6]; }()); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, sparse arrays ? function(){ var iterator = (function * generator() { yield * [,,]; }()); var item = iterator.next(); var passed = item.value === void undefined && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, strings ? function(){ var iterator = (function * generator() { yield * "56"; }()); var item = iterator.next(); var passed = item.value === "5" && item.done === false; item = iterator.next(); passed &= item.value === "6" && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, astral plane strings ? function(){ var iterator = (function * generator() { yield * "𠮷𠮶"; }()); var item = iterator.next(); var passed = item.value === "𠮷" && item.done === false; item = iterator.next(); passed &= item.value === "𠮶" && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, generator instances ? function(){ var iterator = (function * generator() { yield * (function*(){ yield 5; yield 6; yield 7; }()); }()); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === 7 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, generic iterables ? function(){ var iterator = (function * generator() { yield * global.__createIterableObject([5, 6, 7]); }()); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === 7 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, instances of iterables ? function(){ var iterator = (function * generator() { yield * Object.create(__createIterableObject([5, 6, 7])); }()); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === 7 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield * on non-iterables is a runtime error ? function(){ var iterator = (function * generator() { yield * [5]; }()); var item = iterator.next(); var passed = item.value === 5 && item.done === false; iterator = (function * generator() { yield * 5; }()); try { iterator.next(); } catch (e) { return passed; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, iterator closing ? function(){ var closed = ''; var iter = __createIterableObject([1, 2, 3], { 'return': function(){ closed += 'a'; return {done: true}; } }); var gen = (function* generator(){ try { yield *iter; } finally { closed += 'b'; } })(); gen.next(); gen['return'](); return closed === 'ab'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
yield *, iterator closing via throw() ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'throw': undefined, 'return': function() { closed = true; return {done: true}; } }); var gen = (function*(){ try { yield *iter; } catch(e){} })(); gen.next(); gen['throw'](); return closed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
shorthand generator methods ? function(){ var o = { * generator() { yield 5; yield 6; } }; var iterator = o.generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
string-keyed shorthand generator methods ? function(){ var o = { * "foo bar"() { yield 5; yield 6; } }; var iterator = o["foo bar"](); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
computed shorthand generators ? function(){ var garply = "generator"; var o = { * [garply] () { yield 5; yield 6; } }; var iterator = o.generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
shorthand generator methods, classes ? function(){ class C { * generator() { yield 5; yield 6; } }; var iterator = new C().generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
computed shorthand generators, classes ? function(){ var garply = "generator"; class C { * [garply] () { yield 5; yield 6; } } var iterator = new C().generator(); var item = iterator.next(); var passed = item.value === 5 && item.done === false; item = iterator.next(); passed &= item.value === 6 && item.done === false; item = iterator.next(); passed &= item.value === void undefined && item.done === true; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
shorthand generators can't be constructors ? function(){ class C { * generator() { yield 5; yield 6; } }; try { Function("class D { * constructor() { return {}; } }"); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
built-ins

### typed arrays
Int8Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Int8Array(buffer); view[0] = 0x80; return view[0] === -0x80; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Uint8Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Uint8Array(buffer); view[0] = 0x100; return view[0] === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Uint8ClampedArray ? function(){ var buffer = new ArrayBuffer(64); var view = new Uint8ClampedArray(buffer); view[0] = 0x100; return view[0] === 0xFF; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Int16Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Int16Array(buffer); view[0] = 0x8000; return view[0] === -0x8000; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Uint16Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Uint16Array(buffer); view[0] = 0x10000; return view[0] === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Int32Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Int32Array(buffer); view[0] = 0x80000000; return view[0] === -0x80000000; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Uint32Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Uint32Array(buffer); view[0] = 0x100000000; return view[0] === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Float32Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Float32Array(buffer); view[0] = 0.1; return view[0] === 0.10000000149011612; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Float64Array ? function(){ var buffer = new ArrayBuffer(64); var view = new Float64Array(buffer); view[0] = 0.1; return view[0] === 0.1; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Int8) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setInt8 (0, 0x80); return view.getInt8(0) === -0x80; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Uint8) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setUint8(0, 0x100); return view.getUint8(0) === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Int16) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setInt16(0, 0x8000); return view.getInt16(0) === -0x8000; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Uint16) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setUint16(0, 0x10000); return view.getUint16(0) === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Int32) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setInt32(0, 0x80000000); return view.getInt32(0) === -0x80000000; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Uint32) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setUint32(0, 0x100000000); return view.getUint32(0) === 0; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Float32) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setFloat32(0, 0.1); return view.getFloat32(0) === 0.10000000149011612; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
DataView (Float64) ? function(){ var buffer = new ArrayBuffer(64); var view = new DataView(buffer); view.setFloat64(0, 0.1); return view.getFloat64(0) === 0.1; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
ArrayBuffer[Symbol.species] ? function(){ return typeof ArrayBuffer[Symbol.species] === 'function'; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
constructors require new ? function(){ var buffer = new ArrayBuffer(64); var constructors = [ 'ArrayBuffer', 'DataView', 'Int8Array', 'Uint8Array', 'Uint8ClampedArray', 'Int16Array', 'Uint16Array', 'Int32Array', 'Uint32Array', 'Float32Array', 'Float64Array' ]; return constructors.every(function (constructor) { try { if (constructor in global) { global[constructor](constructor === "ArrayBuffer" ? 64 : buffer); } return false; } catch(e) { return true; } }); } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
constructors accept generic iterables ? function(){ var constructors = [ 'Int8Array', 'Uint8Array', 'Uint8ClampedArray', 'Int16Array', 'Uint16Array', 'Int32Array', 'Uint32Array', 'Float32Array', 'Float64Array' ]; for(var i = 0; i < constructors.length; i++){ var arr = new global[constructors[i]](__createIterableObject([1, 2, 3])); if(arr.length !== 3 || arr[0] !== 1 || arr[1] !== 2 || arr[2] !== 3)return false; } return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chains ? function(){ var constructors = [ 'Int8Array', 'Uint8Array', 'Uint8ClampedArray', 'Int16Array', 'Uint16Array', 'Int32Array', 'Uint32Array', 'Float32Array', 'Float64Array' ]; var constructor = Object.getPrototypeOf(Int8Array); var prototype = Object.getPrototypeOf(Int8Array.prototype); if(constructor === Function.prototype || prototype === Object.prototype)return false; for(var i = 0; i < constructors.length; i+=1) { if (!(constructors[i] in global && Object.getPrototypeOf(global[constructors[i]]) === constructor && Object.getPrototypeOf(global[constructors[i]].prototype) === prototype && Object.getOwnPropertyNames(global[constructors[i]].prototype).sort() + '' === "BYTES_PER_ELEMENT,constructor")) { return false; } } return true; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
%TypedArray%.from ? function(){ return typeof Int8Array.from === "function" && typeof Uint8Array.from === "function" && typeof Uint8ClampedArray.from === "function" && typeof Int16Array.from === "function" && typeof Uint16Array.from === "function" && typeof Int32Array.from === "function" && typeof Uint32Array.from === "function" && typeof Float32Array.from === "function" && typeof Float64Array.from === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
%TypedArray%.of ? function(){ return typeof Int8Array.of === "function" && typeof Uint8Array.of === "function" && typeof Uint8ClampedArray.of === "function" && typeof Int16Array.of === "function" && typeof Uint16Array.of === "function" && typeof Int32Array.of === "function" && typeof Uint32Array.of === "function" && typeof Float32Array.of === "function" && typeof Float64Array.of === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
%TypedArray%.prototype.subarray ? function(){ return typeof Int8Array.prototype.subarray === "function" && typeof Uint8Array.prototype.subarray === "function" && typeof Uint8ClampedArray.prototype.subarray === "function" && typeof Int16Array.prototype.subarray === "function" && typeof Uint16Array.prototype.subarray === "function" && typeof Int32Array.prototype.subarray === "function" && typeof Uint32Array.prototype.subarray === "function" && typeof Float32Array.prototype.subarray === "function" && typeof Float64Array.prototype.subarray === "function"; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
%TypedArray%.prototype.join ? function(){ return typeof Int8Array.prototype.join === "function" && typeof Uint8Array.prototype.join === "function" && typeof Uint8ClampedArray.prototype.join === "function" && typeof Int16Array.prototype.join === "function" && typeof Uint16Array.prototype.join === "function" && typeof Int32Array.prototype.join === "function" && typeof Uint32Array.prototype.join === "function" && typeof Float32Array.prototype.join === "function" && typeof Float64Array.prototype.join === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.indexOf ? function(){ return typeof Int8Array.prototype.indexOf === "function" && typeof Uint8Array.prototype.indexOf === "function" && typeof Uint8ClampedArray.prototype.indexOf === "function" && typeof Int16Array.prototype.indexOf === "function" && typeof Uint16Array.prototype.indexOf === "function" && typeof Int32Array.prototype.indexOf === "function" && typeof Uint32Array.prototype.indexOf === "function" && typeof Float32Array.prototype.indexOf === "function" && typeof Float64Array.prototype.indexOf === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.lastIndexOf ? function(){ return typeof Int8Array.prototype.lastIndexOf === "function" && typeof Uint8Array.prototype.lastIndexOf === "function" && typeof Uint8ClampedArray.prototype.lastIndexOf === "function" && typeof Int16Array.prototype.lastIndexOf === "function" && typeof Uint16Array.prototype.lastIndexOf === "function" && typeof Int32Array.prototype.lastIndexOf === "function" && typeof Uint32Array.prototype.lastIndexOf === "function" && typeof Float32Array.prototype.lastIndexOf === "function" && typeof Float64Array.prototype.lastIndexOf === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.slice ? function(){ return typeof Int8Array.prototype.slice === "function" && typeof Uint8Array.prototype.slice === "function" && typeof Uint8ClampedArray.prototype.slice === "function" && typeof Int16Array.prototype.slice === "function" && typeof Uint16Array.prototype.slice === "function" && typeof Int32Array.prototype.slice === "function" && typeof Uint32Array.prototype.slice === "function" && typeof Float32Array.prototype.slice === "function" && typeof Float64Array.prototype.slice === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.every ? function(){ return typeof Int8Array.prototype.every === "function" && typeof Uint8Array.prototype.every === "function" && typeof Uint8ClampedArray.prototype.every === "function" && typeof Int16Array.prototype.every === "function" && typeof Uint16Array.prototype.every === "function" && typeof Int32Array.prototype.every === "function" && typeof Uint32Array.prototype.every === "function" && typeof Float32Array.prototype.every === "function" && typeof Float64Array.prototype.every === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.filter ? function(){ return typeof Int8Array.prototype.filter === "function" && typeof Uint8Array.prototype.filter === "function" && typeof Uint8ClampedArray.prototype.filter === "function" && typeof Int16Array.prototype.filter === "function" && typeof Uint16Array.prototype.filter === "function" && typeof Int32Array.prototype.filter === "function" && typeof Uint32Array.prototype.filter === "function" && typeof Float32Array.prototype.filter === "function" && typeof Float64Array.prototype.filter === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.forEach ? function(){ return typeof Int8Array.prototype.forEach === "function" && typeof Uint8Array.prototype.forEach === "function" && typeof Uint8ClampedArray.prototype.forEach === "function" && typeof Int16Array.prototype.forEach === "function" && typeof Uint16Array.prototype.forEach === "function" && typeof Int32Array.prototype.forEach === "function" && typeof Uint32Array.prototype.forEach === "function" && typeof Float32Array.prototype.forEach === "function" && typeof Float64Array.prototype.forEach === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.map ? function(){ return typeof Int8Array.prototype.map === "function" && typeof Uint8Array.prototype.map === "function" && typeof Uint8ClampedArray.prototype.map === "function" && typeof Int16Array.prototype.map === "function" && typeof Uint16Array.prototype.map === "function" && typeof Int32Array.prototype.map === "function" && typeof Uint32Array.prototype.map === "function" && typeof Float32Array.prototype.map === "function" && typeof Float64Array.prototype.map === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.reduce ? function(){ return typeof Int8Array.prototype.reduce === "function" && typeof Uint8Array.prototype.reduce === "function" && typeof Uint8ClampedArray.prototype.reduce === "function" && typeof Int16Array.prototype.reduce === "function" && typeof Uint16Array.prototype.reduce === "function" && typeof Int32Array.prototype.reduce === "function" && typeof Uint32Array.prototype.reduce === "function" && typeof Float32Array.prototype.reduce === "function" && typeof Float64Array.prototype.reduce === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.reduceRight ? function(){ return typeof Int8Array.prototype.reduceRight === "function" && typeof Uint8Array.prototype.reduceRight === "function" && typeof Uint8ClampedArray.prototype.reduceRight === "function" && typeof Int16Array.prototype.reduceRight === "function" && typeof Uint16Array.prototype.reduceRight === "function" && typeof Int32Array.prototype.reduceRight === "function" && typeof Uint32Array.prototype.reduceRight === "function" && typeof Float32Array.prototype.reduceRight === "function" && typeof Float64Array.prototype.reduceRight === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.reverse ? function(){ return typeof Int8Array.prototype.reverse === "function" && typeof Uint8Array.prototype.reverse === "function" && typeof Uint8ClampedArray.prototype.reverse === "function" && typeof Int16Array.prototype.reverse === "function" && typeof Uint16Array.prototype.reverse === "function" && typeof Int32Array.prototype.reverse === "function" && typeof Uint32Array.prototype.reverse === "function" && typeof Float32Array.prototype.reverse === "function" && typeof Float64Array.prototype.reverse === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.some ? function(){ return typeof Int8Array.prototype.some === "function" && typeof Uint8Array.prototype.some === "function" && typeof Uint8ClampedArray.prototype.some === "function" && typeof Int16Array.prototype.some === "function" && typeof Uint16Array.prototype.some === "function" && typeof Int32Array.prototype.some === "function" && typeof Uint32Array.prototype.some === "function" && typeof Float32Array.prototype.some === "function" && typeof Float64Array.prototype.some === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.sort ? function(){ return typeof Int8Array.prototype.sort === "function" && typeof Uint8Array.prototype.sort === "function" && typeof Uint8ClampedArray.prototype.sort === "function" && typeof Int16Array.prototype.sort === "function" && typeof Uint16Array.prototype.sort === "function" && typeof Int32Array.prototype.sort === "function" && typeof Uint32Array.prototype.sort === "function" && typeof Float32Array.prototype.sort === "function" && typeof Float64Array.prototype.sort === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.copyWithin ? function(){ return typeof Int8Array.prototype.copyWithin === "function" && typeof Uint8Array.prototype.copyWithin === "function" && typeof Uint8ClampedArray.prototype.copyWithin === "function" && typeof Int16Array.prototype.copyWithin === "function" && typeof Uint16Array.prototype.copyWithin === "function" && typeof Int32Array.prototype.copyWithin === "function" && typeof Uint32Array.prototype.copyWithin === "function" && typeof Float32Array.prototype.copyWithin === "function" && typeof Float64Array.prototype.copyWithin === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.find ? function(){ return typeof Int8Array.prototype.find === "function" && typeof Uint8Array.prototype.find === "function" && typeof Uint8ClampedArray.prototype.find === "function" && typeof Int16Array.prototype.find === "function" && typeof Uint16Array.prototype.find === "function" && typeof Int32Array.prototype.find === "function" && typeof Uint32Array.prototype.find === "function" && typeof Float32Array.prototype.find === "function" && typeof Float64Array.prototype.find === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.findIndex ? function(){ return typeof Int8Array.prototype.findIndex === "function" && typeof Uint8Array.prototype.findIndex === "function" && typeof Uint8ClampedArray.prototype.findIndex === "function" && typeof Int16Array.prototype.findIndex === "function" && typeof Uint16Array.prototype.findIndex === "function" && typeof Int32Array.prototype.findIndex === "function" && typeof Uint32Array.prototype.findIndex === "function" && typeof Float32Array.prototype.findIndex === "function" && typeof Float64Array.prototype.findIndex === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.fill ? function(){ return typeof Int8Array.prototype.fill === "function" && typeof Uint8Array.prototype.fill === "function" && typeof Uint8ClampedArray.prototype.fill === "function" && typeof Int16Array.prototype.fill === "function" && typeof Uint16Array.prototype.fill === "function" && typeof Int32Array.prototype.fill === "function" && typeof Uint32Array.prototype.fill === "function" && typeof Float32Array.prototype.fill === "function" && typeof Float64Array.prototype.fill === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.keys ? function(){ return typeof Int8Array.prototype.keys === "function" && typeof Uint8Array.prototype.keys === "function" && typeof Uint8ClampedArray.prototype.keys === "function" && typeof Int16Array.prototype.keys === "function" && typeof Uint16Array.prototype.keys === "function" && typeof Int32Array.prototype.keys === "function" && typeof Uint32Array.prototype.keys === "function" && typeof Float32Array.prototype.keys === "function" && typeof Float64Array.prototype.keys === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.values ? function(){ return typeof Int8Array.prototype.values === "function" && typeof Uint8Array.prototype.values === "function" && typeof Uint8ClampedArray.prototype.values === "function" && typeof Int16Array.prototype.values === "function" && typeof Uint16Array.prototype.values === "function" && typeof Int32Array.prototype.values === "function" && typeof Uint32Array.prototype.values === "function" && typeof Float32Array.prototype.values === "function" && typeof Float64Array.prototype.values === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype.entries ? function(){ return typeof Int8Array.prototype.entries === "function" && typeof Uint8Array.prototype.entries === "function" && typeof Uint8ClampedArray.prototype.entries === "function" && typeof Int16Array.prototype.entries === "function" && typeof Uint16Array.prototype.entries === "function" && typeof Int32Array.prototype.entries === "function" && typeof Uint32Array.prototype.entries === "function" && typeof Float32Array.prototype.entries === "function" && typeof Float64Array.prototype.entries === "function"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | Yes Yes
%TypedArray%.prototype[Symbol.iterator] ? function(){ return typeof Int8Array.prototype[Symbol.iterator] === "function" && typeof Uint8Array.prototype[Symbol.iterator] === "function" && typeof Uint8ClampedArray.prototype[Symbol.iterator] === "function" && typeof Int16Array.prototype[Symbol.iterator] === "function" && typeof Uint16Array.prototype[Symbol.iterator] === "function" && typeof Int32Array.prototype[Symbol.iterator] === "function" && typeof Uint32Array.prototype[Symbol.iterator] === "function" && typeof Float32Array.prototype[Symbol.iterator] === "function" && typeof Float64Array.prototype[Symbol.iterator] === "function"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
%TypedArray%[Symbol.species] ? function(){ return typeof Int8Array[Symbol.species] === "function" && typeof Uint8Array[Symbol.species] === "function" && typeof Uint8ClampedArray[Symbol.species] === "function" && typeof Int16Array[Symbol.species] === "function" && typeof Uint16Array[Symbol.species] === "function" && typeof Int32Array[Symbol.species] === "function" && typeof Uint32Array[Symbol.species] === "function" && typeof Float32Array[Symbol.species] === "function" && typeof Float64Array[Symbol.species] === "function"; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error Flag | Yes Yes
### Map
basic functionality ? function(){ var key = {}; var map = new Map(); map.set(key, 123); return map.has(key) && map.get(key) === 123; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor arguments ? function(){ var key1 = {}; var key2 = {}; var map = new Map([[key1, 123], [key2, 456]]); return map.has(key1) && map.get(key1) === 123 && map.has(key2) && map.get(key2) === 456; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor requires new ? function(){ new Map(); try { Map(); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor accepts null ? function(){ new Map(null); return true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor invokes set ? function(){ var passed = false; var _set = Map.prototype.set; Map.prototype.set = function(k, v) { passed = true; }; new Map([ [1, 2] ]); Map.prototype.set = _set; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); try { new Map(iter); } catch(e){} return closed; } | No No | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
Map.prototype.set returns this ? function(){ var map = new Map(); return map.set(0, 0) === map; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
-0 key converts to +0 ? function(){ var map = new Map(); map.set(-0, "foo"); var k; map.forEach(function (value, key) { k = 1 / key; }); return k === Infinity && map.get(+0) === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.size ? function(){ var key = {}; var map = new Map(); map.set(key, 123); return map.size === 1; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.delete ? function(){ return typeof Map.prototype.delete === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.clear ? function(){ return typeof Map.prototype.clear === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.forEach ? function(){ return typeof Map.prototype.forEach === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.keys ? function(){ return typeof Map.prototype.keys === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.values ? function(){ return typeof Map.prototype.values === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype.entries ? function(){ return typeof Map.prototype.entries === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype[Symbol.iterator] ? function(){ return typeof Map.prototype[Symbol.iterator] === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map.prototype isn't an instance ? function(){ new Map(); var obj = {}; try { Map.prototype.has(obj); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Map iterator prototype chain ? function(){ // Iterator instance var iterator = new Map()[Symbol.iterator](); // %MapIteratorPrototype% var proto1 = Object.getPrototypeOf(iterator); // %IteratorPrototype% var proto2 = Object.getPrototypeOf(proto1); return proto2.hasOwnProperty(Symbol.iterator) && !proto1 .hasOwnProperty(Symbol.iterator) && !iterator .hasOwnProperty(Symbol.iterator) && iterator[Symbol.iterator]() === iterator; } | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | No No
Map[Symbol.species] ? function(){ var prop = Object.getOwnPropertyDescriptor(Map, Symbol.species); return 'get' in prop && Map[Symbol.species] === Map; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
### Set
basic functionality ? function(){ var obj = {}; var set = new Set(); set.add(123); set.add(123); return set.has(123); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor arguments ? function(){ var obj1 = {}; var obj2 = {}; var set = new Set([obj1, obj2]); return set.has(obj1) && set.has(obj2); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor requires new ? function(){ new Set(); try { Set(); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor accepts null ? function(){ new Set(null); return true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor invokes add ? function(){ var passed = false; var _add = Set.prototype.add; Set.prototype.add = function(v) { passed = true; }; new Set([1]); Set.prototype.add = _add; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); var add = Set.prototype.add; Set.prototype.add = function(){ throw 0 }; try { new Set(iter); } catch(e){} Set.prototype.add = add; return closed; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.add returns this ? function(){ var set = new Set(); return set.add(0) === set; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
-0 key converts to +0 ? function(){ var set = new Set(); set.add(-0); var k; set.forEach(function (value) { k = 1 / value; }); return k === Infinity && set.has(+0); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.size ? function(){ var obj = {}; var set = new Set(); set.add(123); set.add(123); set.add(456); return set.size === 2; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.delete ? function(){ return typeof Set.prototype.delete === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.clear ? function(){ return typeof Set.prototype.clear === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.forEach ? function(){ return typeof Set.prototype.forEach === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.keys ? function(){ return typeof Set.prototype.keys === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.values ? function(){ return typeof Set.prototype.values === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype.entries ? function(){ return typeof Set.prototype.entries === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype[Symbol.iterator] ? function(){ return typeof Set.prototype[Symbol.iterator] === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set.prototype isn't an instance ? function(){ new Set(); var obj = {}; try { Set.prototype.has(obj); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Set iterator prototype chain ? function(){ // Iterator instance var iterator = new Set()[Symbol.iterator](); // %SetIteratorPrototype% var proto1 = Object.getPrototypeOf(iterator); // %IteratorPrototype% var proto2 = Object.getPrototypeOf(proto1); return proto2.hasOwnProperty(Symbol.iterator) && !proto1 .hasOwnProperty(Symbol.iterator) && !iterator .hasOwnProperty(Symbol.iterator) && iterator[Symbol.iterator]() === iterator; } | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | No No
Set[Symbol.species] ? function(){ var prop = Object.getOwnPropertyDescriptor(Set, Symbol.species); return 'get' in prop && Set[Symbol.species] === Set; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
### WeakMap
basic functionality ? function(){ var key = {}; var weakmap = new WeakMap(); weakmap.set(key, 123); return weakmap.has(key) && weakmap.get(key) === 123; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor arguments ? function(){ var key1 = {}; var key2 = {}; var weakmap = new WeakMap([[key1, 123], [key2, 456]]); return weakmap.has(key1) && weakmap.get(key1) === 123 && weakmap.has(key2) && weakmap.get(key2) === 456; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor requires new ? function(){ new WeakMap(); try { WeakMap(); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor accepts null ? function(){ new WeakMap(null); return true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor invokes set ? function(){ var passed = false; var _set = WeakMap.prototype.set; WeakMap.prototype.set = function(k, v) { passed = true; }; new WeakMap([ [{ }, 42] ]); WeakMap.prototype.set = _set; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
frozen objects as keys ? function(){ var f = Object.freeze({}); var m = new WeakMap; m.set(f, 42); return m.get(f) === 42; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); try { new WeakMap(iter); } catch(e){} return closed; } | No No | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
WeakMap.prototype.set returns this ? function(){ var weakmap = new WeakMap(); var key = {}; return weakmap.set(key, 0) === weakmap; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
WeakMap.prototype.delete ? function(){ return typeof WeakMap.prototype.delete === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
no WeakMap.prototype.clear method ? function(){ if (!("clear" in WeakMap.prototype)) { return true; } var m = new WeakMap(); var key = {}; m.set(key, 2); m.clear(); return m.has(key); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
.has, .get and .delete methods accept primitives ? function(){ var m = new WeakMap; return m.has(1) === false && m.get(1) === void undefined && m.delete(1) === false; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
WeakMap.prototype isn't an instance ? function(){ new WeakMap(); var obj = {}; try { WeakMap.prototype.has(obj); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
### WeakSet
basic functionality ? function(){ var obj1 = {}; var weakset = new WeakSet(); weakset.add(obj1); weakset.add(obj1); return weakset.has(obj1); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor arguments ? function(){ var obj1 = {}, obj2 = {}; var weakset = new WeakSet([obj1, obj2]); return weakset.has(obj1) && weakset.has(obj2); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor requires new ? function(){ new WeakSet(); try { WeakSet(); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor accepts null ? function(){ new WeakSet(null); return true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
constructor invokes add ? function(){ var passed = false; var _add = WeakSet.prototype.add; WeakSet.prototype.add = function(v) { passed = true; }; new WeakSet([ { } ]); WeakSet.prototype.add = _add; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); try { new WeakSet(iter); } catch(e){} return closed; } | No No | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
WeakSet.prototype.add returns this ? function(){ var weakset = new WeakSet(); var obj = {}; return weakset.add(obj) === weakset; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
WeakSet.prototype.delete ? function(){ return typeof WeakSet.prototype.delete === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
no WeakSet.prototype.clear method ? function(){ if (!("clear" in WeakSet.prototype)) { return true; } var s = new WeakSet(); var key = {}; s.add(key); s.clear(); return s.has(key); } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
.has and .delete methods accept primitives ? function(){ var s = new WeakSet; return s.has(1) === false && s.delete(1) === false; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
WeakSet.prototype isn't an instance ? function(){ new WeakSet(); var obj = {}; try { WeakSet.prototype.has(obj); } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
### Proxy
constructor requires new ? function(){ new Proxy({}, {}); try { Proxy({}, {}); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
no "prototype" property ? function(){ new Proxy({}, {}); return !Proxy.hasOwnProperty('prototype'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"get" handler ? function(){ var proxied = { }; var proxy = new Proxy(proxied, { get: function (t, k, r) { return t === proxied && k === "foo" && r === proxy && 5; } }); return proxy.foo === 5; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"get" handler, instances of proxies ? function(){ var proxied = { }; var proxy = Object.create(new Proxy(proxied, { get: function (t, k, r) { return t === proxied && k === "foo" && r === proxy && 5; } })); return proxy.foo === 5; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"get" handler invariants ? function(){ var passed = false; var proxied = { }; var proxy = new Proxy(proxied, { get: function () { passed = true; return 4; } }); // The value reported for a property must be the same as the value of the corresponding // target object property if the target object property is a non-writable, // non-configurable own data property. Object.defineProperty(proxied, "foo", { value: 5, enumerable: true }); try { proxy.foo; return false; } catch(e) {} // The value reported for a property must be undefined if the corresponding target // object property is a non-configurable own accessor property that has undefined // as its [[Get]] attribute. Object.defineProperty(proxied, "bar", { set: function(){}, enumerable: true }); try { proxy.bar; return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"set" handler ? function(){ var proxied = { }; var passed = false; var proxy = new Proxy(proxied, { set: function (t, k, v, r) { passed = t === proxied && k + v === "foobar" && r === proxy; } }); proxy.foo = "bar"; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"set" handler, instances of proxies ? function(){ var proxied = { }; var passed = false; var proxy = Object.create(new Proxy(proxied, { set: function (t, k, v, r) { passed = t === proxied && k + v === "foobar" && r === proxy; } })); proxy.foo = "bar"; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"set" handler invariants ? function(){ var passed = false; new Proxy({},{}); // Cannot change the value of a property to be different from the value of // the corresponding target object if the corresponding target object // property is a non-writable, non-configurable own data property. var proxied = {}; var proxy = new Proxy(proxied, { set: function () { passed = true; return true; } }); Object.defineProperty(proxied, "foo", { value: 2, enumerable: true }); proxy.foo = 2; try { proxy.foo = 4; return false; } catch(e) {} // Cannot set the value of a property if the corresponding target // object property is a non-configurable own accessor property // that has undefined as its [[Set]] attribute. Object.defineProperty(proxied, "bar", { get: function(){}, enumerable: true }); try { proxy.bar = 2; return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"has" handler ? function(){ var proxied = {}; var passed = false; "foo" in new Proxy(proxied, { has: function (t, k) { passed = t === proxied && k === "foo"; } }); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"has" handler, instances of proxies ? function(){ var proxied = {}; var passed = false; "foo" in Object.create(new Proxy(proxied, { has: function (t, k) { passed = t === proxied && k === "foo"; } })); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"has" handler invariants ? function(){ var passed = false; new Proxy({},{}); // A property cannot be reported as non-existent, if it exists as a // non-configurable own property of the target object. var proxied = {}; var proxy = new Proxy(proxied, { has: function () { passed = true; return false; } }); Object.defineProperty(proxied, "foo", { value: 2, writable: true, enumerable: true }); try { 'foo' in proxy; return false; } catch(e) {} // A property cannot be reported as non-existent, if it exists as an // own property of the target object and the target object is not extensible. proxied.bar = 2; Object.preventExtensions(proxied); try { 'bar' in proxy; return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"deleteProperty" handler ? function(){ var proxied = {}; var passed = false; delete new Proxy(proxied, { deleteProperty: function (t, k) { passed = t === proxied && k === "foo"; } }).foo; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"deleteProperty" handler invariant ? function(){ var passed = false; new Proxy({},{}); // A property cannot be reported as deleted, if it exists as a non-configurable // own property of the target object. var proxied = {}; Object.defineProperty(proxied, "foo", { value: 2, writable: true, enumerable: true }); try { delete new Proxy(proxied, { deleteProperty: function () { passed = true; return true; } }).foo; return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"getOwnPropertyDescriptor" handler ? function(){ var proxied = {}; var fakeDesc = { value: "foo", configurable: true }; var returnedDesc = Object.getOwnPropertyDescriptor( new Proxy(proxied, { getOwnPropertyDescriptor: function (t, k) { return t === proxied && k === "foo" && fakeDesc; } }), "foo" ); return (returnedDesc.value === fakeDesc.value && returnedDesc.configurable === fakeDesc.configurable && returnedDesc.writable === false && returnedDesc.enumerable === false); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"getOwnPropertyDescriptor" handler invariants ? function(){ var passed = false; new Proxy({},{}); // A property cannot be reported as non-existent, if it exists as a non-configurable // own property of the target object. var proxied = {}; var proxy = new Proxy(proxied, { getOwnPropertyDescriptor: function () { passed = true; return undefined; } }); Object.defineProperty(proxied, "foo", { value: 2, writable: true, enumerable: true }); try { Object.getOwnPropertyDescriptor(proxy, "foo"); return false; } catch(e) {} // A property cannot be reported as non-existent, if it exists as an own property // of the target object and the target object is not extensible. proxied.bar = 3; Object.preventExtensions(proxied); try { Object.getOwnPropertyDescriptor(proxy, "bar"); return false; } catch(e) {} // A property cannot be reported as existent, if it does not exists as an own property // of the target object and the target object is not extensible. try { Object.getOwnPropertyDescriptor(new Proxy(proxied, { getOwnPropertyDescriptor: function() { return { value: 2, configurable: true, writable: true, enumerable: true }; }}), "baz"); return false; } catch(e) {} // A property cannot be reported as non-configurable, if it does not exists as an own // property of the target object or if it exists as a configurable own property of // the target object. try { Object.getOwnPropertyDescriptor(new Proxy({}, { getOwnPropertyDescriptor: function() { return { value: 2, configurable: false, writable: true, enumerable: true }; }}), "baz"); return false; } catch(e) {} try { Object.getOwnPropertyDescriptor(new Proxy({baz:1}, { getOwnPropertyDescriptor: function() { return { value: 1, configurable: false, writable: true, enumerable: true }; }}), "baz"); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"defineProperty" handler ? function(){ var proxied = {}; var passed = false; Object.defineProperty( new Proxy(proxied, { defineProperty: function (t, k, d) { passed = t === proxied && k === "foo" && d.value === 5; return true; } }), "foo", { value: 5, configurable: true } ); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"defineProperty" handler invariants ? function(){ var passed = false; new Proxy({},{}); // A property cannot be added, if the target object is not extensible. var proxied = Object.preventExtensions({}); var proxy = new Proxy(proxied, { defineProperty: function() { passed = true; return true; } }); try { Object.defineProperty(proxy, "foo", { value: 2 }); return false; } catch(e) {} // A property cannot be non-configurable, unless there exists a corresponding // non-configurable own property of the target object. try { Object.defineProperty( new Proxy({ bar: true }, { defineProperty: function () { return true; } }), "bar", { value: 5, configurable: false, writable: true, enumerable: true } ); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"getPrototypeOf" handler ? function(){ var proxied = {}; var fakeProto = {}; var proxy = new Proxy(proxied, { getPrototypeOf: function (t) { return t === proxied && fakeProto; } }); return Object.getPrototypeOf(proxy) === fakeProto; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"getPrototypeOf" handler invariant ? function(){ var passed = false; new Proxy({},{}); // If the target object is not extensible, [[GetPrototypeOf]] applied to the proxy object // must return the same value as [[GetPrototypeOf]] applied to the proxy object's target object. try { Object.getPrototypeOf(new Proxy(Object.preventExtensions({}), { getPrototypeOf: function () { passed = true; return {}; } })); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"setPrototypeOf" handler ? function(){ var proxied = {}; var newProto = {}; var passed = false; Object.setPrototypeOf( new Proxy(proxied, { setPrototypeOf: function (t, p) { passed = t === proxied && p === newProto; return true; } }), newProto ); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"setPrototypeOf" handler invariant ? function(){ var passed = false; new Proxy({},{}); Object.setPrototypeOf({},{}); // If the target object is not extensible, the argument value must be the // same as the result of [[GetPrototypeOf]] applied to target object. try { Object.setPrototypeOf( new Proxy(Object.preventExtensions({}), { setPrototypeOf: function () { passed = true; return true; } }),{}); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"isExtensible" handler ? function(){ var proxied = {}; var passed = false; Object.isExtensible( new Proxy(proxied, { isExtensible: function (t) { passed = t === proxied; return true; } }) ); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"isExtensible" handler invariant ? function(){ var passed = false; new Proxy({},{}); // [[IsExtensible]] applied to the proxy object must return the same value // as [[IsExtensible]] applied to the proxy object's target object with the same argument. try { Object.isExtensible(new Proxy({}, { isExtensible: function (t) { passed = true; return false; } })); return false; } catch(e) {} try { Object.isExtensible(new Proxy(Object.preventExtensions({}), { isExtensible: function (t) { return true; } })); return false; } catch(e) {} return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"preventExtensions" handler ? function(){ var proxied = {}; var passed = false; Object.preventExtensions( new Proxy(proxied, { preventExtensions: function (t) { passed = t === proxied; return Object.preventExtensions(proxied); } }) ); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"preventExtensions" handler invariant ? function(){ var passed = false; new Proxy({},{}); // [[PreventExtensions]] applied to the proxy object only returns true // if [[IsExtensible]] applied to the proxy object's target object is false. try { Object.preventExtensions(new Proxy({}, { preventExtensions: function () { passed = true; return true; } })); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"ownKeys" handler ? function(){ var proxied = {}; var passed = false; Object.keys( new Proxy(proxied, { ownKeys: function (t) { passed = t === proxied; return []; } }) ); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"ownKeys" handler invariant ? function(){ var passed = false; new Proxy({},{}); // The Type of each result List element is either String or Symbol. try { Object.keys(new Proxy({}, { ownKeys: function () { passed = true; return [2]; }})); return false; } catch(e) {} // The result List must contain the keys of all non-configurable own properties of the target object. var proxied = {}; Object.defineProperty(proxied, "foo", { value: 2, writable: true, enumerable: true }); try { Object.keys(new Proxy(proxied, { ownKeys: function () { return []; }})); return false; } catch(e) {} // If the target object is not extensible, then the result List must contain all the keys // of the own properties of the target object and no other values. try { Object.keys(new Proxy(Object.preventExtensions({b:1}), { ownKeys: function () { return ['a']; }})); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"apply" handler ? function(){ var proxied = function(){}; var passed = false; var host = { method: new Proxy(proxied, { apply: function (t, thisArg, args) { passed = t === proxied && thisArg === host && args + "" === "foo,bar"; } }) }; host.method("foo", "bar"); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
"apply" handler invariant ? function(){ var passed = false; new Proxy(function(){}, { apply: function () { passed = true; } })(); // A Proxy exotic object only has a [[Call]] internal method if the // initial value of its [[ProxyTarget]] internal slot is an object // that has a [[Call]] internal method. try { new Proxy({}, { apply: function () {} })(); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"construct" handler ? function(){ var proxied = function(){}; var passed = false; new new Proxy(proxied, { construct: function (t, args) { passed = t === proxied && args + "" === "foo,bar"; return {}; } })("foo","bar"); return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
"construct" handler invariants ? function(){ var passed = false; new Proxy({},{}); // A Proxy exotic object only has a [[Construct]] internal method if the // initial value of its [[ProxyTarget]] internal slot is an object // that has a [[Construct]] internal method. try { new new Proxy({}, { construct: function (t, args) { return {}; } })(); return false; } catch(e) {} // The result of [[Construct]] must be an Object. try { new new Proxy(function(){}, { construct: function (t, args) { passed = true; return 5; } })(); return false; } catch(e) {} return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Proxy.revocable ? function(){ var obj = Proxy.revocable({}, { get: function() { return 5; } }); var passed = (obj.proxy.foo === 5); obj.revoke(); try { obj.proxy.foo; } catch(e) { passed &= e instanceof TypeError; } return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.isArray support ? function(){ return Array.isArray(new Proxy([], {})); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
JSON.stringify support ? function(){ return JSON.stringify(new Proxy(['foo'], {})) === '["foo"]'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### Reflect
Reflect.get ? function(){ return Reflect.get({ qux: 987 }, "qux") === 987; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.set ? function(){ var obj = {}; Reflect.set(obj, "quux", 654); return obj.quux === 654; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.has ? function(){ return Reflect.has({ qux: 987 }, "qux"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.deleteProperty ? function(){ var obj = { bar: 456 }; Reflect.deleteProperty(obj, "bar"); return !("bar" in obj); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.getOwnPropertyDescriptor ? function(){ var obj = { baz: 789 }; var desc = Reflect.getOwnPropertyDescriptor(obj, "baz"); return desc.value === 789 && desc.configurable && desc.writable && desc.enumerable; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.defineProperty ? function(){ var obj = {}; Reflect.defineProperty(obj, "foo", { value: 123 }); return obj.foo === 123 && Reflect.defineProperty(Object.freeze({}), "foo", { value: 123 }) === false; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.getPrototypeOf ? function(){ return Reflect.getPrototypeOf([]) === Array.prototype; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.setPrototypeOf ? function(){ var obj = {}; Reflect.setPrototypeOf(obj, Array.prototype); return obj instanceof Array; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.isExtensible ? function(){ return Reflect.isExtensible({}) && !Reflect.isExtensible(Object.preventExtensions({})); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.preventExtensions ? function(){ var obj = {}; Reflect.preventExtensions(obj); return !Object.isExtensible(obj); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.ownKeys, string keys ? function(){ var obj = Object.create({ C: true }); obj.A = true; Object.defineProperty(obj, 'B', { value: true, enumerable: false }); return Reflect.ownKeys(obj).sort() + '' === "A,B"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.ownKeys, symbol keys ? function(){ var s1 = Symbol(), s2 = Symbol(), s3 = Symbol(); var proto = {}; proto[s1] = true; var obj = Object.create(proto); obj[s2] = true; Object.defineProperty(obj, s3, { value: true, enumerable: false }); var keys = Reflect.ownKeys(obj); return keys.indexOf(s2) >-1 && keys.indexOf(s3) >-1 && keys.length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.apply ? function(){ return Reflect.apply(Array.prototype.push, [1,2], [3,4,5]) === 5; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.construct ? function(){ return Reflect.construct(function(a, b, c) { this.qux = a + b + c; }, ["foo", "bar", "baz"]).qux === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.construct sets new.target meta-property ? function(){ return Reflect.construct(function(a, b, c) { if (new.target === Object) { this.qux = a + b + c; } }, ["foo", "bar", "baz"], Object).qux === "foobarbaz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Reflect.construct creates instances from third argument ? function(){ function F(){} var obj = Reflect.construct(function(){ this.y = 1; }, [], F); return obj.y === 1 && obj instanceof F; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.construct, Array subclassing ? function(){ function F(){} var obj = Reflect.construct(Array, [], F); obj[2] = 'foo'; return obj.length === 3 && obj instanceof F; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.construct, RegExp subclassing ? function(){ function F(){} var obj = Reflect.construct(RegExp, ["baz","g"], F); return RegExp.prototype.exec.call(obj, "foobarbaz")[0] === "baz" && obj.lastIndex === 9 && obj instanceof F; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Reflect.construct, Function subclassing ? function(){ function F(){} var obj = Reflect.construct(Function, ["return 2"], F); return obj() === 2 && obj instanceof F; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.construct, Promise subclassing ? function(){ function F(){} var p1 = Reflect.construct(Promise,[function(resolve, reject) { resolve("foo"); }], F); var p2 = Reflect.construct(Promise,[function(resolve, reject) { reject("quux"); }], F); var score = +(p1 instanceof F && p2 instanceof F); function thenFn(result) { score += (result === "foo"); check(); } function catchFn(result) { score += (result === "quux"); check(); } function shouldNotRun(result) { score = -Infinity; } p1.then = p2.then = Promise.prototype.then; p1.catch = p2.catch = Promise.prototype.catch; p1.then(thenFn, shouldNotRun); p2.then(shouldNotRun, catchFn); p1.catch(shouldNotRun); p2.catch(catchFn); function check() { if (score === 4) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Promise
basic functionality ? function(){ var p1 = new Promise(function(resolve, reject) { resolve("foo"); }); var p2 = new Promise(function(resolve, reject) { reject("quux"); }); var score = 0; function thenFn(result) { score += (result === "foo"); check(); } function catchFn(result) { score += (result === "quux"); check(); } function shouldNotRun(result) { score = -Infinity; } p1.then(thenFn, shouldNotRun); p2.then(shouldNotRun, catchFn); p1.catch(shouldNotRun); p2.catch(catchFn); p1.then(function() { // Promise.prototype.then() should return a new Promise score += p1.then() !== p1; check(); }); function check() { if (score === 4) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
constructor requires new ? function(){ new Promise(function(){}); try { Promise(function(){}); return false; } catch(e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise.prototype isn't an instance ? function(){ new Promise(function(){}); try { Promise.prototype.then(function(){}); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise.all ? function(){ var fulfills = Promise.all([ new Promise(function(resolve) { setTimeout(resolve,2000,"foo"); }), new Promise(function(resolve) { setTimeout(resolve,1000,"bar"); }) ]); var rejects = Promise.all([ new Promise(function(_, reject) { setTimeout(reject, 2000,"baz"); }), new Promise(function(_, reject) { setTimeout(reject, 1000,"qux"); }) ]); var score = 0; fulfills.then(function(result) { score += (result + "" === "foo,bar"); check(); }); rejects.catch(function(result) { score += (result === "qux"); check(); }); function check() { if (score === 2) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise.all, generic iterables ? function(){ var fulfills = Promise.all(global.__createIterableObject([ new Promise(function(resolve) { setTimeout(resolve,2000,"foo"); }), new Promise(function(resolve) { setTimeout(resolve,1000,"bar"); }) ])); var rejects = Promise.all(global.__createIterableObject([ new Promise(function(_, reject) { setTimeout(reject, 2000,"baz"); }), new Promise(function(_, reject) { setTimeout(reject, 1000,"qux"); }) ])); var score = 0; fulfills.then(function(result) { score += (result + "" === "foo,bar"); check(); }); rejects.catch(function(result) { score += (result === "qux"); check(); }); function check() { if (score === 2) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise.race ? function(){ var fulfills = Promise.race([ new Promise(function(resolve) { setTimeout(resolve,1000,"foo"); }), new Promise(function(_, reject) { setTimeout(reject, 2000,"bar"); }) ]); var rejects = Promise.race([ new Promise(function(_, reject) { setTimeout(reject, 1000,"baz"); }), new Promise(function(resolve) { setTimeout(resolve,2000,"qux"); }) ]); var score = 0; fulfills.then(function(result) { score += (result === "foo"); check(); }); rejects.catch(function(result) { score += (result === "baz"); check(); }); function check() { if (score === 2) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise.race, generic iterables ? function(){ var fulfills = Promise.race(global.__createIterableObject([ new Promise(function(resolve) { setTimeout(resolve,1000,"foo"); }), new Promise(function(_, reject) { setTimeout(reject, 2000,"bar"); }) ])); var rejects = Promise.race(global.__createIterableObject([ new Promise(function(_, reject) { setTimeout(reject, 1000,"baz"); }), new Promise(function(resolve) { setTimeout(resolve,2000,"qux"); }) ])); var score = 0; fulfills.then(function(result) { score += (result === "foo"); check(); }); rejects.catch(function(result) { score += (result === "baz"); check(); }); function check() { if (score === 2) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Promise[Symbol.species] ? function(){ var prop = Object.getOwnPropertyDescriptor(Promise, Symbol.species); return 'get' in prop && Promise[Symbol.species] === Promise; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
### Symbol
basic functionality ? function(){ var object = {}; var symbol = Symbol(); var value = {}; object[symbol] = value; return object[symbol] === value; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
typeof support ? function(){ return typeof Symbol() === "symbol"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
symbol keys are hidden to pre-ES6 code ? function(){ var object = {}; var symbol = Symbol(); object[symbol] = 1; for (var x in object){} var passed = !x; if (Object.keys && Object.getOwnPropertyNames) { passed &= Object.keys(object).length === 0 && Object.getOwnPropertyNames(object).length === 0; } return passed; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.defineProperty support ? function(){ var object = {}; var symbol = Symbol(); var value = {}; if (Object.defineProperty) { Object.defineProperty(object, symbol, { value: value }); return object[symbol] === value; } return passed; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
symbols inherit from Symbol.prototype ? function(){ var symbol = Symbol(); var passed = symbol.foo === void undefined; Symbol.prototype.foo = 2; passed &= symbol.foo === 2; delete Symbol.prototype.foo; return passed; } | Error Error | Error Error | Error No | Error No | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
cannot coerce to string or number ? function(){ var symbol = Symbol(); try { symbol + ""; return false; } catch(e) {} try { symbol + 0; return false; } catch(e) {} return true; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
can convert with String() ? function(){ return String(Symbol("foo")) === "Symbol(foo)"; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
new Symbol() throws ? function(){ var symbol = Symbol(); try { new Symbol(); } catch(e) { return true; } } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object(symbol) ? function(){ var symbol = Symbol(); var symbolObject = Object(symbol); return typeof symbolObject === "object" && symbolObject instanceof Symbol && symbolObject == symbol && // eslint-disable-line eqeqeq symbolObject !== symbol && symbolObject.valueOf() === symbol; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | Yes Yes
JSON.stringify ignores symbol primitives ? function(){ var object = { foo: Symbol() }; object[Symbol()] = 1; var array = [Symbol()]; return JSON.stringify(object) === '{}' && JSON.stringify(array) === '[null]' && JSON.stringify(Symbol()) === void undefined; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error Flag | Yes Yes
JSON.stringify ignores symbol objects ? function(){ var testSymbolObject = function (sym) { var object = { foo: sym }; try { // some browsers throw a TypeError when setting symbol object keys. // this isn't part of this test, so, ignore it if so. object[sym] = 1; } catch (e) {} // some browsers throw a TypeError when setting symbol object keys. var array = [sym]; return JSON.stringify(object) === '{"foo":{}}' && JSON.stringify(array) === '[{}]' && JSON.stringify(sym) === '{}'; }; var objSym = Object(Symbol()); var symNoToJSON = Object(Symbol()); Object.defineProperty(symNoToJSON, 'toJSON', { enumerable: false, value: null }); // ensure it overrides the prototype, but is not callable return testSymbolObject(objSym) && testSymbolObject(symNoToJSON); } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
global symbol registry ? function(){ var symbol = Symbol.for('foo'); return Symbol.for('foo') === symbol && Symbol.keyFor(symbol) === 'foo'; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
### well-known symbols
Symbol.hasInstance ? function(){ var passed = false; var obj = { foo: true }; var C = function(){}; Object.defineProperty(C, Symbol.hasInstance, { value: function(inst) { passed = inst.foo; return false; } }); obj instanceof C; return passed; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.isConcatSpreadable, non-spreadable array ? function(){ var a = [], b = []; b[Symbol.isConcatSpreadable] = false; a = a.concat(b); return a[0] === b; } | Error Error | Error Error | Error No | Error No | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Symbol.isConcatSpreadable, spreadable object with poisoned getter ? function(){ if (typeof Symbol !== 'function' || !Symbol.isConcatSpreadable) { return null; } var spreadableHasPoisonedIndex = { length: Math.pow(2, 53) - 1 }; spreadableHasPoisonedIndex[Symbol.isConcatSpreadable] = true; Object.defineProperty(spreadableHasPoisonedIndex, 0, { get: function () { throw new SyntaxError(); } }); try { [].concat(spreadableHasPoisonedIndex); return false; } catch (e) { return !!e && e.name === 'SyntaxError'; } } | No No | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
Symbol.iterator, existence ? function(){ return "iterator" in Symbol; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Symbol.iterator, arguments object ? function(){ return (function() { return typeof arguments[Symbol.iterator] === 'function' && Object.hasOwnProperty.call(arguments, Symbol.iterator); }()); } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Symbol.species, existence ? function(){ return "species" in Symbol; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Symbol.species, Array.prototype.concat ? function(){ var obj = []; obj.constructor = {}; obj.constructor[Symbol.species] = function() { return { foo: 1 }; }; return Array.prototype.concat.call(obj, []).foo === 1; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, Array.prototype.filter ? function(){ var obj = []; obj.constructor = {}; obj.constructor[Symbol.species] = function() { return { foo: 1 }; }; return Array.prototype.filter.call(obj, Boolean).foo === 1; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, Array.prototype.map ? function(){ var obj = []; obj.constructor = {}; obj.constructor[Symbol.species] = function() { return { foo: 1 }; }; return Array.prototype.map.call(obj, Boolean).foo === 1; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, Array.prototype.slice ? function(){ var obj = []; obj.constructor = {}; obj.constructor[Symbol.species] = function() { return { foo: 1 }; }; return Array.prototype.slice.call(obj, 0).foo === 1; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, Array.prototype.splice ? function(){ var obj = []; obj.constructor = {}; obj.constructor[Symbol.species] = function() { return { foo: 1 }; }; return Array.prototype.splice.call(obj, 0).foo === 1; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, RegExp.prototype[Symbol.split] ? function(){ var passed = false; var obj = { constructor: {} }; obj[Symbol.split] = RegExp.prototype[Symbol.split]; obj.constructor[Symbol.species] = function() { passed = true; return /./; }; "".split(obj); return passed; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.species, Promise.prototype.then ? function(){ var promise = new Promise(function(resolve){ resolve(42); }); var FakePromise1 = promise.constructor = function(exec){ exec(function(){}, function(){}); }; var FakePromise2 = function(exec){ exec(function(){}, function(){}); }; Object.defineProperty(FakePromise1, Symbol.species, {value: FakePromise2}); return promise.then(function(){}) instanceof FakePromise2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Symbol.replace ? function(){ var O = {}; O[Symbol.replace] = function(){ return 42; }; return ''.replace(O) === 42; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.search ? function(){ var O = {}; O[Symbol.search] = function(){ return 42; }; return ''.search(O) === 42; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.split ? function(){ var O = {}; O[Symbol.split] = function(){ return 42; }; return ''.split(O) === 42; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.match ? function(){ var O = {}; O[Symbol.match] = function(){ return 42; }; return ''.match(O) === 42; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.match, RegExp constructor ? function(){ var re = /./; re[Symbol.match] = false; var foo = {constructor: RegExp}; foo[Symbol.match] = true; return RegExp(re) !== re && RegExp(foo) === foo; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Symbol.match, String.prototype.startsWith ? function(){ var re = /./; try { '/./'.startsWith(re); } catch(e){ re[Symbol.match] = false; return '/./'.startsWith(re); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
Symbol.match, String.prototype.endsWith ? function(){ var re = /./; try { '/./'.endsWith(re); } catch(e){ re[Symbol.match] = false; return '/./'.endsWith(re); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
Symbol.match, String.prototype.includes ? function(){ var re = /./; try { '/./'.includes(re); } catch(e){ re[Symbol.match] = false; return '/./'.includes(re); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
Symbol.toPrimitive ? function(){ var a = {}, b = {}, c = {}; var passed = 0; a[Symbol.toPrimitive] = function(hint) { passed += hint === "number"; return 0; }; b[Symbol.toPrimitive] = function(hint) { passed += hint === "string"; return 0; }; c[Symbol.toPrimitive] = function(hint) { passed += hint === "default"; return 0; }; a >= 0; b in {}; c == 0; // eslint-disable-line eqeqeq return passed === 3; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | Yes Yes
Symbol.toStringTag ? function(){ var a = {}; a[Symbol.toStringTag] = "foo"; return (a + "") === "[object foo]"; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | Yes Yes
Symbol.toStringTag affects existing built-ins ? function(){ var s = Symbol.toStringTag; var passed = true; [ [Array.prototype, []], [String.prototype, ''], [arguments, arguments], [Function.prototype, function(){}], [Error.prototype, new Error()], [Boolean.prototype, true], [Number.prototype, 2], [Date.prototype, new Date()], [RegExp.prototype, /./] ].forEach(function(pair){ pair[0][s] = "foo"; passed &= (Object.prototype.toString.call(pair[1]) === "[object foo]"); delete pair[0][s]; }); return passed; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | Yes Yes
Symbol.toStringTag, new built-ins ? function(){ var passed = true; var s = Symbol.toStringTag; [ [String, "String Iterator"], [Array, "Array Iterator"], [Map, "Map Iterator"], [Set, "Set Iterator"] ].forEach(function(pair){ var iterProto = Object.getPrototypeOf(new pair[0]()[Symbol.iterator]()); passed = passed && iterProto.hasOwnProperty(s) && iterProto[s] === pair[1]; }); passed = passed && Object.getPrototypeOf(function*(){})[s] === "GeneratorFunction" && Object.getPrototypeOf(function*(){}())[s] === "Generator" && Map.prototype[s] === "Map" && Set.prototype[s] === "Set" && ArrayBuffer.prototype[s] === "ArrayBuffer" && DataView.prototype[s] === "DataView" && Promise.prototype[s] === "Promise" && Symbol.prototype[s] === "Symbol" && typeof Object.getOwnPropertyDescriptor( Object.getPrototypeOf(Int8Array).prototype, Symbol.toStringTag).get === "function"; return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | No No
Symbol.toStringTag, misc. built-ins ? function(){ var s = Symbol.toStringTag; return Math[s] === "Math" && JSON[s] === "JSON"; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error Flag | Yes Yes
Symbol.unscopables ? function(){ var a = { foo: 1, bar: 2 }; a[Symbol.unscopables] = { bar: true }; with (a) { return foo === 1 && typeof bar === "undefined"; } } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No

##
built-in extensions

### Object static methods
Object.assign ? function(){ var o = Object.assign({a:true}, {b:true}, {c:true}); return "a" in o && "b" in o && "c" in o; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Object.is ? function(){ return typeof Object.is === 'function' && Object.is(NaN, NaN) && !Object.is(-0, 0); } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Object.getOwnPropertySymbols ? function(){ var o = {}; var sym = Symbol(), sym2 = Symbol(), sym3 = Symbol(); o[sym] = true; o[sym2] = true; o[sym3] = true; var result = Object.getOwnPropertySymbols(o); return result[0] === sym && result[1] === sym2 && result[2] === sym3; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.setPrototypeOf ? function(){ return Object.setPrototypeOf({}, Array.prototype) instanceof Array; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
### function "name" property
function statements ? function(){ function foo(){}; return foo.name === 'foo' && (function(){}).name === ''; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
function expressions ? function(){ return (function foo(){}).name === 'foo' && (function(){}).name === ''; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
new Function ? function(){ return (new Function).name === "anonymous"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
bound functions ? function(){ function foo() {}; return foo.bind({}).name === "bound foo" && (function(){}).bind({}).name === "bound "; } | No No | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes
variables (function) ? function(){ var foo = function() {}; var bar = function baz() {}; return foo.name === "foo" && bar.name === "baz"; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
object methods (function) ? function(){ var o = { foo: function(){}, bar: function baz(){}}; o.qux = function(){}; return o.foo.name === "foo" && o.bar.name === "baz" && o.qux.name === ""; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
accessor properties ? function(){ var o = { get foo(){}, set foo(x){} }; var descriptor = Object.getOwnPropertyDescriptor(o, "foo"); return descriptor.get.name === "get foo" && descriptor.set.name === "set foo"; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
shorthand methods ? function(){ var o = { foo(){} }; return o.foo.name === "foo"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
shorthand methods (no lexical binding) ? function(){ var f = "foo"; return ({f() { return f; }}).f() === "foo"; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
symbol-keyed methods ? function(){ var sym1 = Symbol("foo"); var sym2 = Symbol(); var o = { [sym1]: function(){}, [sym2]: function(){} }; return o[sym1].name === "[foo]" && o[sym2].name === ""; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
class statements ? function(){ class foo {}; class bar { static name() {} }; return foo.name === "foo" && typeof bar.name === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
class expressions ? function(){ return class foo {}.name === "foo" && typeof class bar { static name() {} }.name === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
variables (class) ? function(){ var foo = class {}; var bar = class baz {}; var qux = class { static name() {} }; return foo.name === "foo" && bar.name === "baz" && typeof qux.name === "function"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
object methods (class) ? function(){ var o = { foo: class {}, bar: class baz {}}; o.qux = class {}; return o.foo.name === "foo" && o.bar.name === "baz" && o.qux.name === ""; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
class prototype methods ? function(){ class C { foo(){} }; return (new C).foo.name === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
class static methods ? function(){ class C { static foo(){} }; return C.foo.name === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
isn't writable, is configurable ? function(){ var descriptor = Object.getOwnPropertyDescriptor(function f(){},"name"); return descriptor.enumerable === false && descriptor.writable === false && descriptor.configurable === true; } | No No | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes
### String static methods
String.raw ? function(){ return typeof String.raw === 'function'; } | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
String.fromCodePoint ? function(){ return typeof String.fromCodePoint === 'function'; } | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### String.prototype methods
String.prototype.codePointAt ? function(){ return typeof String.prototype.codePointAt === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.normalize ? function(){ return typeof String.prototype.normalize === "function" && "c\u0327\u0301".normalize("NFC") === "\u1e09" && "\u1e09".normalize("NFD") === "c\u0327\u0301"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.repeat ? function(){ return typeof String.prototype.repeat === 'function' && "foo".repeat(3) === "foofoofoo"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.startsWith ? function(){ return typeof String.prototype.startsWith === 'function' && "foobar".startsWith("foo"); } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.startsWith throws on RegExp ? function(){ try { "a".startsWith(/./); } catch(e) { return typeof String.prototype.startsWith === 'function'; } } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.endsWith ? function(){ return typeof String.prototype.endsWith === 'function' && "foobar".endsWith("bar"); } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.endsWith throws on RegExp ? function(){ try { "a".endsWith(/./); } catch(e) { return typeof String.prototype.endsWith === 'function'; } } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.includes ? function(){ return typeof String.prototype.includes === 'function' && "foobar".includes("oba"); } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype[Symbol.iterator] ? function(){ return typeof String.prototype[Symbol.iterator] === 'function'; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
String iterator prototype chain ? function(){ // Iterator instance var iterator = ''[Symbol.iterator](); // %StringIteratorPrototype% var proto1 = Object.getPrototypeOf(iterator); // %IteratorPrototype% var proto2 = Object.getPrototypeOf(proto1); return proto2.hasOwnProperty(Symbol.iterator) && !proto1 .hasOwnProperty(Symbol.iterator) && !iterator .hasOwnProperty(Symbol.iterator) && iterator[Symbol.iterator]() === iterator; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
### RegExp.prototype properties
RegExp.prototype.flags ? function(){ return /./igm.flags === "gim" && /./.flags === ""; } | No No | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes
RegExp.prototype[Symbol.match] ? function(){ return typeof RegExp.prototype[Symbol.match] === 'function'; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error Flag | Error Flag | Error Flag | Yes Yes
RegExp.prototype[Symbol.replace] ? function(){ return typeof RegExp.prototype[Symbol.replace] === 'function'; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
RegExp.prototype[Symbol.split] ? function(){ return typeof RegExp.prototype[Symbol.split] === 'function'; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
RegExp.prototype[Symbol.search] ? function(){ return typeof RegExp.prototype[Symbol.search] === 'function'; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error Flag | Error Flag | Error Flag | Yes Yes
RegExp[Symbol.species] ? function(){ var prop = Object.getOwnPropertyDescriptor(RegExp, Symbol.species); return 'get' in prop && RegExp[Symbol.species] === RegExp; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
### Array static methods
Array.from, array-like objects ? function(){ return Array.from({ 0: "foo", 1: "bar", length: 2 }) + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.from, generator instances ? function(){ var iterable = (function*(){ yield 1; yield 2; yield 3; }()); return Array.from(iterable) + '' === "1,2,3"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No Flag | No Flag | No Flag | Yes Yes
Array.from, generic iterables ? function(){ var iterable = global.__createIterableObject([1, 2, 3]); return Array.from(iterable) + '' === "1,2,3"; } | Error Error | Error Error | Error Error | Error Error | No Error | No Flag | No Flag | No Flag | No Flag | Yes Yes
Array.from, instances of generic iterables ? function(){ var iterable = global.__createIterableObject([1, 2, 3]); return Array.from(Object.create(iterable)) + '' === "1,2,3"; } | Error Error | Error Error | Error Error | Error Error | No Error | No Flag | No Flag | No Flag | No Flag | Yes Yes
Array.from map function, array-like objects ? function(){ return Array.from({ 0: "foo", 1: "bar", length: 2 }, function(e, i) { return e + this.baz + i; }, { baz: "d" }) + '' === "food0,bard1"; } | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.from map function, generator instances ? function(){ var iterable = (function*(){ yield "foo"; yield "bar"; yield "bal"; }()); return Array.from(iterable, function(e, i) { return e + this.baz + i; }, { baz: "d" }) + '' === "food0,bard1,bald2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No Flag | No Flag | No Flag | Yes Yes
Array.from map function, generic iterables ? function(){ var iterable = global.__createIterableObject(["foo", "bar", "bal"]); return Array.from(iterable, function(e, i) { return e + this.baz + i; }, { baz: "d" }) + '' === "food0,bard1,bald2"; } | Error Error | Error Error | Error Error | Error Error | No Error | No Flag | No Flag | No Flag | No Flag | Yes Yes
Array.from map function, instances of iterables ? function(){ var iterable = global.__createIterableObject(["foo", "bar", "bal"]); return Array.from(Object.create(iterable), function(e, i) { return e + this.baz + i; }, { baz: "d" }) + '' === "food0,bard1,bald2"; } | Error Error | Error Error | Error Error | Error Error | No Error | No Flag | No Flag | No Flag | No Flag | Yes Yes
Array.from, iterator closing ? function(){ var closed = false; var iter = global.__createIterableObject([1, 2, 3], { 'return': function(){ closed = true; return {}; } }); try { Array.from(iter, function() { throw 42 }); } catch(e){} return closed; } | No No | No No | No No | No No | No Flag | No Flag | No Flag | No Flag | No Flag | Yes Yes
Array.of ? function(){ return typeof Array.of === 'function' && Array.of(2)[0] === 2; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array[Symbol.species] ? function(){ var prop = Object.getOwnPropertyDescriptor(Array, Symbol.species); return 'get' in prop && Array[Symbol.species] === Array; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Yes Yes
### Array.prototype methods
Array.prototype.copyWithin ? function(){ return typeof Array.prototype.copyWithin === 'function'; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.find ? function(){ return typeof Array.prototype.find === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.findIndex ? function(){ return typeof Array.prototype.findIndex === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.fill ? function(){ return typeof Array.prototype.fill === 'function'; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.keys ? function(){ return typeof Array.prototype.keys === 'function'; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.values ? function(){ return typeof Array.prototype.values === 'function'; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.entries ? function(){ return typeof Array.prototype.entries === 'function'; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.splice ? function(){ if ([0, 1, 2].splice(0).length !== 3) { // IE <= 8 and other pre-ES6 engines fail this check return false; } var a = [1, 2]; var result = a.splice(); if (a.length !== 2 || result.length !== 0) { // Safari 5.0 has this bug return false; } var obj = {}; Array.prototype.splice.call(obj, 0, 0, 1); if (obj.length !== 1) { return false; } var spliceWorksWithLargeSparseArrays = (function () { // Per https://github.com/es-shims/es5-shim/issues/295 // Safari 7/8 breaks with sparse arrays of size 1e5 or greater var arr = new Array(1e5); // note: the index MUST be 8 or larger or the test will false pass arr[8] = 'x'; arr.splice(1, 1); for (var i = 0; i < arr.length; i += 1) { if (arr[i] === 'x') { return i === 7; } } return false; }()); var spliceWorksWithSmallSparseArrays = (function () { // Per https://github.com/es-shims/es5-shim/issues/295 // Opera 12.15 breaks on this, no idea why. var n = 256; var arr = []; arr[n] = 'a'; arr.splice(n + 1, 0, 'b'); return arr[n] === 'a'; }()); return spliceWorksWithLargeSparseArrays && spliceWorksWithSmallSparseArrays; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype[Symbol.iterator] ? function(){ return typeof Array.prototype[Symbol.iterator] === 'function'; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Array iterator prototype chain ? function(){ // Iterator instance var iterator = [][Symbol.iterator](); // %ArrayIteratorPrototype% var proto1 = Object.getPrototypeOf(iterator); // %IteratorPrototype% var proto2 = Object.getPrototypeOf(proto1); return proto2.hasOwnProperty(Symbol.iterator) && !proto1 .hasOwnProperty(Symbol.iterator) && !iterator .hasOwnProperty(Symbol.iterator) && iterator[Symbol.iterator]() === iterator; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | No No
Array.prototype[Symbol.unscopables] ? function(){ var unscopables = Array.prototype[Symbol.unscopables]; if (!unscopables) { return false; } var ns = "find,findIndex,fill,copyWithin,entries,keys,values".split(","); for (var i = 0; i < ns.length; i++) { if (Array.prototype[ns[i]] && !unscopables[ns[i]]) return false; } return true; } | Error Error | Error Error | Error No | Error No | Error No | Error No | Error No | Error No | Error No | Yes Yes
### Number properties
Number.isFinite ? function(){ return typeof Number.isFinite === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Number.isInteger ? function(){ return typeof Number.isInteger === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Number.isSafeInteger ? function(){ return typeof Number.isSafeInteger === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Number.isNaN ? function(){ return typeof Number.isNaN === 'function'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Number.parseFloat ? function(){ var actualGlobal = Function('return this')(); return typeof Number.parseFloat === 'function' && Number.parseFloat === actualGlobal.parseFloat; } | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
Number.parseInt ? function(){ var actualGlobal = Function('return this')(); return typeof Number.parseInt === 'function' && Number.parseInt === actualGlobal.parseInt; } | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
Number.EPSILON ? function(){ return typeof Number.EPSILON === 'number'; } | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
Number.MIN_SAFE_INTEGER ? function(){ return typeof Number.MIN_SAFE_INTEGER === 'number'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Number.MAX_SAFE_INTEGER ? function(){ return typeof Number.MAX_SAFE_INTEGER === 'number'; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### Math methods
Math.clz32 ? function(){ return typeof Math.clz32 === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.imul ? function(){ return typeof Math.imul === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.sign ? function(){ return typeof Math.sign === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.log10 ? function(){ return typeof Math.log10 === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.log2 ? function(){ return typeof Math.log2 === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.log1p ? function(){ return typeof Math.log1p === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.expm1 ? function(){ return typeof Math.expm1 === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.cosh ? function(){ return typeof Math.cosh === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.sinh ? function(){ return typeof Math.sinh === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.tanh ? function(){ return typeof Math.tanh === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.acosh ? function(){ return typeof Math.acosh === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.asinh ? function(){ return typeof Math.asinh === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.atanh ? function(){ return typeof Math.atanh === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.trunc ? function(){ return typeof Math.trunc === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.fround ? function(){ return typeof Math.fround === "function"; } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.cbrt ? function(){ return typeof Math.cbrt === "function"; } | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Math.hypot ? function(){ return Math.hypot() === 0 && Math.hypot(1) === 1 && Math.hypot(9, 12, 20) === 25 && Math.hypot(27, 36, 60, 100) === 125; } | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
###
Date.prototype[Symbol.toPrimitive] ? function(){ var tp = Date.prototype[Symbol.toPrimitive]; return tp.call(Object(2), "number") === 2 && tp.call(Object(2), "string") === "2" && tp.call(Object(2), "default") === "2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes

##
subclassing

### Array is subclassable
length property (accessing) ? function(){ class C extends Array {} var c = new C(); var len1 = c.length; c[2] = 'foo'; var len2 = c.length; return len1 === 0 && len2 === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
length property (setting) ? function(){ class C extends Array {} var c = new C(); c[2] = 'foo'; c.length = 1; return c.length === 1 && !(2 in c); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chain ? function(){ class C extends Array {} var c = new C(); return c instanceof C && c instanceof Array && Object.getPrototypeOf(C) === Array; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.isArray support ? function(){ class C extends Array {} return Array.isArray(new C()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.prototype.concat ? function(){ class C extends Array {} var c = new C(); return c.concat(1) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.prototype.filter ? function(){ class C extends Array {} var c = new C(); return c.filter(Boolean) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.prototype.map ? function(){ class C extends Array {} var c = new C(); return c.map(Boolean) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.prototype.slice ? function(){ class C extends Array {} var c = new C(); c.push(2,4,6); return c.slice(1,2) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.prototype.splice ? function(){ class C extends Array {} var c = new C(); c.push(2,4,6); return c.splice(1,2) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.from ? function(){ class C extends Array {} return C.from({ length: 0 }) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.of ? function(){ class C extends Array {} return C.of(0) instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### RegExp is subclassable
basic functionality ? function(){ class R extends RegExp {} var r = new R("baz","g"); return r.global && r.source === "baz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chain ? function(){ class R extends RegExp {} var r = new R("baz","g"); return r instanceof R && r instanceof RegExp && Object.getPrototypeOf(R) === RegExp; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype.exec ? function(){ class R extends RegExp {} var r = new R("baz","g"); return r.exec("foobarbaz")[0] === "baz" && r.lastIndex === 9; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype.test ? function(){ class R extends RegExp {} var r = new R("baz"); return r.test("foobarbaz"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Function is subclassable
can be called ? function(){ class C extends Function {} var c = new C("return 'foo';"); return c() === 'foo'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chain ? function(){ class C extends Function {} var c = new C("return 'foo';"); return c instanceof C && c instanceof Function && Object.getPrototypeOf(C) === Function; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
can be used with "new" ? function(){ class C extends Function {} var c = new C("this.bar = 2;"); c.prototype.baz = 3; return new c().bar === 2 && new c().baz === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Function.prototype.call ? function(){ class C extends Function {} var c = new C("x", "return this.bar + x;"); return c.call({bar:1}, 2) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Function.prototype.apply ? function(){ class C extends Function {} var c = new C("x", "return this.bar + x;"); return c.apply({bar:1}, [2]) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Function.prototype.bind ? function(){ class C extends Function {} var c = new C("x", "y", "return this.bar + x + y;").bind({bar:1}, 2); return c(6) === 9 && c instanceof C; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Promise is subclassable
basic functionality ? function(){ class P extends Promise {} var p1 = new P(function(resolve, reject) { resolve("foo"); }); var p2 = new P(function(resolve, reject) { reject("quux"); }); var score = +(p1 instanceof P); function thenFn(result) { score += (result === "foo"); check(); } function catchFn(result) { score += (result === "quux"); check(); } function shouldNotRun(result) { score = -Infinity; } p1.then(thenFn, shouldNotRun); p2.then(shouldNotRun, catchFn); p1.catch(shouldNotRun); p2.catch(catchFn); p1.then(function() { // P.prototype.then() should return a new P score += p1.then() instanceof P && p1.then() !== p1; check(); }); function check() { if (score === 5) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chain ? function(){ class C extends Promise {} var c = new C(function(resolve, reject) { resolve("foo"); }); return c instanceof C && c instanceof Promise && Object.getPrototypeOf(C) === Promise; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Promise.all ? function(){ class P extends Promise {} var fulfills = P.all([ new Promise(function(resolve) { setTimeout(resolve,2000,"foo"); }), new Promise(function(resolve) { setTimeout(resolve,1000,"bar"); }) ]); var rejects = P.all([ new Promise(function(_, reject) { setTimeout(reject, 2000,"baz"); }), new Promise(function(_, reject) { setTimeout(reject, 1000,"qux"); }) ]); var score = +(fulfills instanceof P); fulfills.then(function(result) { score += (result + "" === "foo,bar"); check(); }); rejects.catch(function(result) { score += (result === "qux"); check(); }); function check() { if (score === 3) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Promise.race ? function(){ class P extends Promise {} var fulfills = P.race([ new Promise(function(resolve) { setTimeout(resolve,1000,"foo"); }), new Promise(function(_, reject) { setTimeout(reject, 2000,"bar"); }) ]); var rejects = P.race([ new Promise(function(_, reject) { setTimeout(reject, 1000,"baz"); }), new Promise(function(resolve) { setTimeout(resolve,2000,"qux"); }) ]); var score = +(fulfills instanceof P); fulfills.then(function(result) { score += (result === "foo"); check(); }); rejects.catch(function(result) { score += (result === "baz"); check(); }); function check() { if (score === 3) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### miscellaneous subclassables
Boolean is subclassable ? function(){ class C extends Boolean {} var c = new C(true); return c instanceof Boolean && c instanceof C && c == true; // eslint-disable-line eqeqeq } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Number is subclassable ? function(){ class C extends Number {} var c = new C(6); return c instanceof Number && c instanceof C && +c === 6; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
String is subclassable ? function(){ class C extends String {} var c = new C("golly"); return c instanceof String && c instanceof C && c + '' === "golly" && c[0] === "g" && c.length === 5; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Error is subclassable ? function(){ class C extends Error {} var c = new C(); return c instanceof Error && c instanceof C && Object.prototype.toString.call(c) === "[object Error]"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Map is subclassable ? function(){ var key = {}; class M extends Map {} var map = new M(); map.set(key, 123); return map instanceof M && map.has(key) && map.get(key) === 123; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Set is subclassable ? function(){ var obj = {}; class S extends Set {} var set = new S(); set.add(123); set.add(123); return set instanceof S && set.has(123); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
misc

### prototype of bound functions
basic functions ? function(){ function correctProtoBound(proto) { var f = function(){}; if (Object.setPrototypeOf) { Object.setPrototypeOf(f, proto); } else { f.__proto__ = proto; } var boundF = Function.prototype.bind.call(f, null); return Object.getPrototypeOf(boundF) === proto; } return correctProtoBound(Function.prototype) && correctProtoBound({}) && correctProtoBound(null); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
generator functions ? function(){ function correctProtoBound(proto) { var f = function*(){}; if (Object.setPrototypeOf) { Object.setPrototypeOf(f, proto); } else { f.__proto__ = proto; } var boundF = Function.prototype.bind.call(f, null); return Object.getPrototypeOf(boundF) === proto; } return correctProtoBound(Function.prototype) && correctProtoBound({}) && correctProtoBound(null); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | No No
arrow functions ? function(){ function correctProtoBound(proto) { var f = ()=>5; if (Object.setPrototypeOf) { Object.setPrototypeOf(f, proto); } else { f.__proto__ = proto; } var boundF = Function.prototype.bind.call(f, null); return Object.getPrototypeOf(boundF) === proto; } return correctProtoBound(Function.prototype) && correctProtoBound({}) && correctProtoBound(null); } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No No | No No
classes ? function(){ function correctProtoBound(proto) { class C {} if (Object.setPrototypeOf) { Object.setPrototypeOf(C, proto); } else { C.__proto__ = proto; } var boundF = Function.prototype.bind.call(C, null); return Object.getPrototypeOf(boundF) === proto; } return correctProtoBound(Function.prototype) && correctProtoBound({}) && correctProtoBound(null); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
subclasses ? function(){ function correctProtoBound(superclass) { class C extends superclass { constructor() { return Object.create(null); } } var boundF = Function.prototype.bind.call(C, null); return Object.getPrototypeOf(boundF) === Object.getPrototypeOf(C); } return correctProtoBound(function(){}) && correctProtoBound(Array) && correctProtoBound(null); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Proxy, internal 'get' calls
ToPrimitive ? function(){ // ToPrimitive -> Get -> [[Get]] var get = []; var p = new Proxy({toString:Function()}, { get: function(o, k) { get.push(k); return o[k]; }}); p + 3; return get[0] === Symbol.toPrimitive && get.slice(1) + '' === "valueOf,toString"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
CreateListFromArrayLike ? function(){ // CreateListFromArrayLike -> Get -> [[Get]] var get = []; var p = new Proxy({length:2, 0:0, 1:0}, { get: function(o, k) { get.push(k); return o[k]; }}); Function.prototype.apply({}, p); return get + '' === "length,0,1"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
instanceof operator ? function(){ // InstanceofOperator -> GetMethod -> GetV -> [[Get]] // InstanceofOperator -> OrdinaryHasInstance -> Get -> [[Get]] var get = []; var p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }}); ({}) instanceof p; return get[0] === Symbol.hasInstance && get.slice(1) + '' === "prototype"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
HasBinding ? function(){ // HasBinding -> Get -> [[Get]] var get = []; var p = new Proxy({foo:1}, { get: function(o, k) { get.push(k); return o[k]; }}); p[Symbol.unscopables] = p; with(p) { typeof foo; } return get[0] === Symbol.unscopables && get.slice(1) + '' === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
CreateDynamicFunction ? function(){ // CreateDynamicFunction -> GetPrototypeFromConstructor -> Get -> [[Get]] var get = []; var p = new Proxy(Function, { get: function(o, k) { get.push(k); return o[k]; }}); new p; return get + '' === "prototype"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
ClassDefinitionEvaluation ? function(){ // ClassDefinitionEvaluation -> Get -> [[Get]] var get = []; var p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }}); class C extends p {} return get + '' === "prototype"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
IteratorComplete, IteratorValue ? function(){ // IteratorComplete -> Get -> [[Get]] // IteratorValue -> Get -> [[Get]] var get = []; var iterable = {}; iterable[Symbol.iterator] = function() { return { next: function() { return new Proxy({ value: 2, done: false }, { get: function(o, k) { get.push(k); return o[k]; }}); } }; } var i = 0; for(var e of iterable) { if (++i >= 2) break; } return get + '' === "done,value,done,value"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
ToPropertyDescriptor ? function(){ // ToPropertyDescriptor -> Get -> [[Get]] var get = []; var p = new Proxy({ enumerable: true, configurable: true, value: true, writable: true, get: Function(), set: Function() }, { get: function(o, k) { get.push(k); return o[k]; }}); try { // This will throw, since it will have true for both "get" and "value", // but not before performing a Get on every property. Object.defineProperty({}, "foo", p); } catch(e) { return get + '' === "enumerable,configurable,value,writable,get,set"; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Object.assign ? function(){ // Object.assign -> Get -> [[Get]] var get = []; var p = new Proxy({foo:1, bar:2}, { get: function(o, k) { get.push(k); return o[k]; }}); Object.assign({}, p); return get + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Object.defineProperties ? function(){ // Object.defineProperties -> Get -> [[Get]] var get = []; var p = new Proxy({foo:{}, bar:{}}, { get: function(o, k) { get.push(k); return o[k]; }}); Object.defineProperties({}, p); return get + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Function.prototype.bind ? function(){ // Function.prototype.bind -> Get -> [[Get]] var get = []; var p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }}); Function.prototype.bind.call(p); return get + '' === "length,name"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Error.prototype.toString ? function(){ // Error.prototype.toString -> Get -> [[Get]] var get = []; var p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }}); Error.prototype.toString.call(p); return get + '' === "name,message"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
String.raw ? function(){ // String.raw -> Get -> [[Get]] var get = []; var raw = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }}); var p = new Proxy({raw: raw}, { get: function(o, k) { get.push(k); return o[k]; }}); String.raw(p); return get + '' === "raw,length,0,1"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
RegExp constructor ? function(){ // RegExp -> Get -> [[Get]] var get = []; var re = { constructor: null }; re[Symbol.match] = true; var p = new Proxy(re, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp(p); return get[0] === Symbol.match && get.slice(1) + '' === "constructor,source,flags"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
RegExp.prototype.flags ? function(){ // RegExp.prototype.flags -> Get -> [[Get]] var expected = []; // Sorted alphabetically by shortname – "gimsuy". if ('hasIndices' in RegExp.prototype) expected.push('hasIndices'); if ('global' in RegExp.prototype) expected.push('global'); if ('ignoreCase' in RegExp.prototype) expected.push('ignoreCase'); if ('multiline' in RegExp.prototype) expected.push('multiline'); if ('dotAll' in RegExp.prototype) expected.push('dotAll'); if ('unicode' in RegExp.prototype) expected.push('unicode'); if ('unicodeSets' in RegExp.prototype) expected.push('unicodeSets'); if ('sticky' in RegExp.prototype) expected.push('sticky'); var actual = []; var p = new Proxy({}, { get: function(o, k) { actual.push(k); return o[k]; }}); Object.getOwnPropertyDescriptor(RegExp.prototype, 'flags').get.call(p); if (expected.length !== actual.length) return false; for (var i = 0; i < expected.length; i++) { if (expected[i] !== actual[i]) return false; } return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype.test ? function(){ // RegExp.prototype.test -> RegExpExec -> Get -> [[Get]] var get = []; var p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype.test.call(p); return get + '' === "exec"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype.toString ? function(){ // RegExp.prototype.toString -> Get -> [[Get]] var get = []; var p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype.toString.call(p); return get + '' === "source,flags"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype[Symbol.match] ? function(){ // RegExp.prototype[Symbol.match] -> Get -> [[Get]] var get = []; var p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype[Symbol.match].call(p); p.global = true; RegExp.prototype[Symbol.match].call(p); var str = get + ''; return str === "global,exec,global,unicode,exec" || str === 'flags,exec,flags,exec'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype[Symbol.replace] ? function(){ // RegExp.prototype[Symbol.replace] -> Get -> [[Get]] var get = []; var p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype[Symbol.replace].call(p); p.global = true; RegExp.prototype[Symbol.replace].call(p); var str = get + ''; return str === "global,exec,global,unicode,exec" || str === 'flags,exec,flags,exec'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype[Symbol.search] ? function(){ // RegExp.prototype[Symbol.search] -> Get -> [[Get]] var get = []; var p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype[Symbol.search].call(p); return get + '' === "lastIndex,exec,lastIndex"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp.prototype[Symbol.split] ? function(){ // RegExp.prototype[Symbol.split] -> Get -> [[Get]] var get = []; var constructor = Function(); constructor[Symbol.species] = Object; var p = new Proxy({ constructor: constructor, flags: '', exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }}); RegExp.prototype[Symbol.split].call(p, ""); return get + '' === "constructor,flags,exec"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.from ? function(){ // Array.from -> Get -> [[Get]] var get = []; var p = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }}); Array.from(p); return get[0] === Symbol.iterator && get.slice(1) + '' === "length,0,1"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.prototype.concat ? function(){ // Array.prototype.concat -> Get -> [[Get]] var get = []; var arr = [1]; arr.constructor = void undefined; var p = new Proxy(arr, { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.concat.call(p,p); return get[0] === "constructor" && get[1] === Symbol.isConcatSpreadable && get[2] === "length" && get[3] === "0" && get[4] === get[1] && get[5] === get[2] && get[6] === get[3] && get.length === 7; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.prototype iteration methods ? function(){ // Array.prototype methods -> Get -> [[Get]] var methods = ['copyWithin', 'every', 'fill', 'filter', 'find', 'findIndex', 'forEach', 'indexOf', 'join', 'lastIndexOf', 'map', 'reduce', 'reduceRight', 'some']; var get; var p = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }}); for(var i = 0; i < methods.length; i+=1) { get = []; Array.prototype[methods[i]].call(p, Function()); if (get + '' !== ( methods[i] === 'fill' ? "length" : methods[i] === 'every' ? "length,0" : methods[i] === 'lastIndexOf' || methods[i] === 'reduceRight' ? "length,1,0" : "length,0,1" )) { return false; } } return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.pop ? function(){ // Array.prototype.pop -> Get -> [[Get]] var get = []; var p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.pop.call(p); return get + '' === "length,3"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.reverse ? function(){ // Array.prototype.reverse -> Get -> [[Get]] var get = []; var p = new Proxy([0,,2,,4,,], { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.reverse.call(p); return get + '' === "length,0,4,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.prototype.shift ? function(){ // Array.prototype.shift -> Get -> [[Get]] var get = []; var p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.shift.call(p); return get + '' === "length,0,1,2,3"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.splice ? function(){ // Array.prototype.splice -> Get -> [[Get]] var get = []; var p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.splice.call(p,1,1); Array.prototype.splice.call(p,1,0,1); return get + '' === "length,constructor,1,2,3,length,constructor,2,1"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.prototype.toString ? function(){ // Array.prototype.toString -> Get -> [[Get]] var get = []; var p = new Proxy({ join:Function() }, { get: function(o, k) { get.push(k); return o[k]; }}); Array.prototype.toString.call(p); return get + '' === "join"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
JSON.stringify ? function(){ // JSON.stringify -> Get -> [[Get]] var get = []; var p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }}); JSON.stringify(p); return get + '' === "toJSON"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Promise resolve functions ? function(){ // Promise resolve functions -> Get -> [[Get]] var get = []; var p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }}); new Promise(function(resolve){ resolve(p); }); return get + '' === "then"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
String.prototype.match ? function(){ // String.prototype.match -> Get -> [[Get]] var get = []; var proxied = {}; proxied[Symbol.toPrimitive] = Function(); var p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }}); "".match(p); return get[0] === Symbol.match && get[1] === Symbol.toPrimitive && get.length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
String.prototype.replace ? function(){ // String.prototype.replace functions -> Get -> [[Get]] var get = []; var proxied = {}; proxied[Symbol.toPrimitive] = Function(); var p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }}); "".replace(p); return get[0] === Symbol.replace && get[1] === Symbol.toPrimitive && get.length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
String.prototype.search ? function(){ // String.prototype.search functions -> Get -> [[Get]] var get = []; var proxied = {}; proxied[Symbol.toPrimitive] = Function(); var p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }}); "".search(p); return get[0] === Symbol.search && get[1] === Symbol.toPrimitive && get.length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
String.prototype.split ? function(){ // String.prototype.split functions -> Get -> [[Get]] var get = []; var proxied = {}; proxied[Symbol.toPrimitive] = Function(); var p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }}); "".split(p); return get[0] === Symbol.split && get[1] === Symbol.toPrimitive && get.length === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Date.prototype.toJSON ? function(){ // Date.prototype.toJSON -> ToPrimitive -> Get -> [[Get]] // Date.prototype.toJSON -> Invoke -> GetMethod -> GetV -> [[Get]] var get = []; var p = new Proxy({toString:Function(),toISOString:Function()}, { get: function(o, k) { get.push(k); return o[k]; }}); Date.prototype.toJSON.call(p); return get[0] === Symbol.toPrimitive && get.slice(1) + '' === "valueOf,toString,toISOString"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### Proxy, internal 'set' calls
Object.assign ? function(){ // Object.assign -> Set -> [[Set]] var set = []; var p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); Object.assign(p, { foo: 1, bar: 2 }); return set + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.from ? function(){ // Array.from -> Set -> [[Set]] var set = []; var p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); Array.from.call(function(){ return p; }, {length:2, 0:1, 1:2}); return set + '' === "length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Array.of ? function(){ // Array.from -> Set -> [[Set]] var set = []; var p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); Array.of.call(function(){ return p; }, 1, 2, 3); return set + '' === "length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.copyWithin ? function(){ // Array.prototype.copyWithin -> Set -> [[Set]] var set = []; var p = new Proxy([1,2,3,4,5,6], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.copyWithin(0, 3); return set + '' === "0,1,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.fill ? function(){ // Array.prototype.fill -> Set -> [[Set]] var set = []; var p = new Proxy([1,2,3,4,5,6], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.fill(0, 3); return set + '' === "3,4,5"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.pop ? function(){ // Array.prototype.pop -> Set -> [[Set]] var set = []; var p = new Proxy([], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.pop(); return set + '' === "length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.push ? function(){ // Array.prototype.push -> Set -> [[Set]] var set = []; var p = new Proxy([], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.push(0,0,0); return set + '' === "0,1,2,length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.reverse ? function(){ // Array.prototype.reverse -> Set -> [[Set]] var set = []; var p = new Proxy([0,0,0,,], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.reverse(); return set + '' === "3,1,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.shift ? function(){ // Array.prototype.shift -> Set -> [[Set]] var set = []; var p = new Proxy([0,0,,0], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.shift(); return set + '' === "0,2,length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.splice ? function(){ // Array.prototype.splice -> Set -> [[Set]] var set = []; var p = new Proxy([1,2,3], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.splice(1,0,0); return set + '' === "3,2,1,length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.unshift ? function(){ // Array.prototype.unshift -> Set -> [[Set]] var set = []; var p = new Proxy([0,0,,0], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }}); p.unshift(0,1); return set + '' === "5,3,2,0,1,length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### Proxy, internal 'defineProperty' calls
[[Set]] ? function(){ // [[Set]] -> [[DefineOwnProperty]] var def = []; var p = new Proxy({foo:1, bar:2}, { defineProperty: function(o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; }}); p.foo = 2; p.bar = 4; return def + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
SetIntegrityLevel ? function(){ // SetIntegrityLevel -> DefinePropertyOrThrow -> [[DefineOwnProperty]] var def = []; var p = new Proxy({foo:1, bar:2}, { defineProperty: function(o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; }}); Object.freeze(p); return def + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### Proxy, internal 'deleteProperty' calls
Array.prototype.copyWithin ? function(){ // Array.prototype.copyWithin -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,0,0,,,,], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.copyWithin(0,3); return del + '' === "0,1,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.pop ? function(){ // Array.prototype.pop -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,0,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.pop(); return del + '' === "2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.reverse ? function(){ // Array.prototype.reverse -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,,2,,4,,], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.reverse(); return del + '' === "0,4,2"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.shift ? function(){ // Array.prototype.shift -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,,0,,0,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.shift(); return del + '' === "0,2,5"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.splice ? function(){ // Array.prototype.splice -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,0,0,0,,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.splice(2,2,0); return del + '' === "3,5"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Array.prototype.unshift ? function(){ // Array.prototype.unshift -> DeletePropertyOrThrow -> [[Delete]] var del = []; var p = new Proxy([0,0,,0,,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }}); p.unshift(0); return del + '' === "5,3"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### Proxy, internal 'getOwnPropertyDescriptor' calls
[[Set]] ? function(){ // [[Set]] -> [[GetOwnProperty]] var gopd = []; var p = new Proxy({}, { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }}); p.foo = 1; p.bar = 1; return gopd + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Object.assign ? function(){ // Object.assign -> [[GetOwnProperty]] var gopd = []; var p = new Proxy({foo:1, bar:2}, { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }}); Object.assign({}, p); return gopd + '' === "foo,bar"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Object.prototype.hasOwnProperty ? function(){ // Object.prototype.hasOwnProperty -> HasOwnProperty -> [[GetOwnProperty]] var gopd = []; var p = new Proxy({foo:1, bar:2}, { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }}); p.hasOwnProperty('garply'); return gopd + '' === "garply"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
Function.prototype.bind ? function(){ // Function.prototype.bind -> HasOwnProperty -> [[GetOwnProperty]] var gopd = []; var p = new Proxy(Function(), { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }}); p.bind(); return gopd + '' === "length"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### Proxy, internal 'ownKeys' calls
SetIntegrityLevel ? function(){ // SetIntegrityLevel -> [[OwnPropertyKeys]] var ownKeysCalled = 0; var p = new Proxy({}, { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }}); Object.freeze(p); return ownKeysCalled === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
TestIntegrityLevel ? function(){ // TestIntegrityLevel -> [[OwnPropertyKeys]] var ownKeysCalled = 0; var p = new Proxy(Object.preventExtensions({}), { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }}); Object.isFrozen(p); return ownKeysCalled === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
SerializeJSONObject ? function(){ // SerializeJSONObject -> EnumerableOwnNames -> [[OwnPropertyKeys]] var ownKeysCalled = 0; var p = new Proxy({}, { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }}); JSON.stringify({a:p,b:p}); return ownKeysCalled === 2; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
### Object static methods accept primitives
Object.getPrototypeOf ? function(){ return Object.getPrototypeOf('a').constructor === String; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.getOwnPropertyDescriptor ? function(){ return Object.getOwnPropertyDescriptor('a', 'foo') === void undefined; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.getOwnPropertyNames ? function(){ var s = Object.getOwnPropertyNames('a'); return s.length === 2 && ((s[0] === 'length' && s[1] === '0') || (s[0] === '0' && s[1] === 'length')); } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.seal ? function(){ return Object.seal('a') === 'a'; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.freeze ? function(){ return Object.freeze('a') === 'a'; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.preventExtensions ? function(){ return Object.preventExtensions('a') === 'a'; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.isSealed ? function(){ return Object.isSealed('a') === true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.isFrozen ? function(){ return Object.isFrozen('a') === true; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.isExtensible ? function(){ return Object.isExtensible('a') === false; } | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
Object.keys ? function(){ var s = Object.keys('a'); return s.length === 1 && s[0] === '0'; } | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Error Flag | Yes Yes
### own property order
Object.keys ? function(){ var obj = { // Non-negative integer names appear first in value order 2: true, 0: true, 1: true, // Other string names appear in source order ' ': true, // Non-negative integers are sorted above other names 9: true, D: true, B: true, // Negative integers are treated as other names '-1': true }; // Other string names are added in order of creation obj.A = true; // Non-negative integer names, conversely, ignore order of creation obj[3] = true; // Having a total of 20+ properties doesn't affect property order "EFGHIJKLMNOPQRSTUVWXYZ".split('').forEach(function(key){ obj[key] = true; }); // Object.defineProperty doesn't affect the above rules Object.defineProperty(obj, 'C', { value: true, enumerable: true }); Object.defineProperty(obj, '4', { value: true, enumerable: true }); // Deleting and reinserting a property doesn't preserve its position delete obj[2]; obj[2] = true; var forInOrder = ''; for(var key in obj)forInOrder += key; return Object.keys(obj).join('') === forInOrder; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Object.getOwnPropertyNames ? function(){ var obj = { 2: true, 0: true, 1: true, ' ': true, 9: true, D: true, B: true, '-1': true }; obj.A = true; obj[3] = true; "EFGHIJKLMNOPQRSTUVWXYZ".split('').forEach(function(key){ obj[key] = true; }); Object.defineProperty(obj, 'C', { value: true, enumerable: true }); Object.defineProperty(obj, '4', { value: true, enumerable: true }); delete obj[2]; obj[2] = true; return Object.getOwnPropertyNames(obj).join('') === "012349 DB-1AEFGHIJKLMNOPQRSTUVWXYZC"; } | No No | No No | No No | No No | No No | No No | No No | No No | No Flag | Yes Yes
Object.assign ? function(){ var result = ''; var target = {}; "012349 DBACEFGHIJKLMNOPQRST".split('').concat(-1).forEach(function(key){ Object.defineProperty(target, key, { set: function(){ result += key; } }) }); var obj = {2: 2, 0: 0, 1: 1, ' ': ' ', 9: 9, D: 'D', B: 'B', '-1': '-1'}; Object.defineProperty(obj, 'A', {value: 'A', enumerable: true}); Object.defineProperty(obj, '3', {value: '3', enumerable: true}); Object.defineProperty(obj, 'C', {value: 'C', enumerable: true}); Object.defineProperty(obj, '4', {value: '4', enumerable: true}); delete obj[2]; obj[2] = true; "EFGHIJKLMNOPQRST".split('').forEach(function(key){ obj[key] = key; }); Object.assign(target, obj); return result === "012349 DB-1ACEFGHIJKLMNOPQRST"; } | Error Error | Error Error | No No | No No | No No | No No | No No | No No | No Flag | Yes Yes
JSON.stringify ? function(){ var obj = { 2: true, 0: true, 1: true, ' ': true, 9: true, D: true, B: true, '-1': true }; obj.A = true; obj[3] = true; "EFGHIJKLMNOPQRSTUVWXYZ".split('').forEach(function(key){ obj[key] = true; }); Object.defineProperty(obj, 'C', { value: true, enumerable: true }); Object.defineProperty(obj, '4', { value: true, enumerable: true }); delete obj[2]; obj[2] = true; return JSON.stringify(obj) === '{"0":true,"1":true,"2":true,"3":true,"4":true,"9":true," ":true,"D":true,"B":true,"-1":true,"A":true,"E":true,"F":true,"G":true,"H":true,"I":true,"J":true,"K":true,"L":true,"M":true,"N":true,"O":true,"P":true,"Q":true,"R":true,"S":true,"T":true,"U":true,"V":true,"W":true,"X":true,"Y":true,"Z":true,"C":true}'; } | No No | No No | No No | No No | No No | No No | No No | No No | No Flag | Yes Yes
JSON.parse ? function(){ var result = ''; JSON.parse( '{"0":true,"1":true,"2":true,"3":true,"4":true,"9":true," ":true,"D":true,"B":true,"-1":true,"E":true,"F":true,"G":true,"H":true,"I":true,"J":true,"K":true,"L":true,"A":true,"C":true}', function reviver(k,v) { result += k; return v; } ); return result === "012349 DB-1EFGHIJKLAC"; } | Yes Yes | Yes Yes | Yes No | Yes No | Yes No | Yes No | Yes No | Yes No | Yes Yes | Yes Yes
Reflect.ownKeys, string key order ? function(){ var obj = { 2: true, 0: true, 1: true, ' ': true, 9: true, D: true, B: true, '-1': true }; obj.A = true; obj[3] = true; "EFGHIJKLMNOPQRSTUVWXYZ".split('').forEach(function(key){ obj[key] = true; }); Object.defineProperty(obj, 'C', { value: true, enumerable: true }); Object.defineProperty(obj, '4', { value: true, enumerable: true }); delete obj[2]; obj[2] = true; return Reflect.ownKeys(obj).join('') === "012349 DB-1AEFGHIJKLMNOPQRSTUVWXYZC"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Reflect.ownKeys, symbol key order ? function(){ var sym1 = Symbol(), sym2 = Symbol(), sym3 = Symbol(); var obj = { 1: true, A: true }; obj.B = true; obj[sym1] = true; obj[2] = true; obj[sym2] = true; Object.defineProperty(obj, 'C', { value: true, enumerable: true }); Object.defineProperty(obj, sym3,{ value: true, enumerable: true }); Object.defineProperty(obj, 'D', { value: true, enumerable: true }); var result = Reflect.ownKeys(obj); var l = result.length; return result[l-3] === sym1 && result[l-2] === sym2 && result[l-1] === sym3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### Updated identifier syntax
var ⸯ; ? function(){ try { eval('var ⸯ'); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
var 𐋀; ? function(){ var 𐋀; return true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
no escaped reserved words as identifiers ? function(){ var \u0061; try { eval('var v\\u0061r'); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No Flag | Yes Yes
### miscellaneous
duplicate property names in strict mode ? function(){ 'use strict'; return this === void undefined && ({ a:1, a:1 }).a === 1; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
no semicolon needed after do-while ? function(){ do {} while (false) return true; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
no assignments allowed in for-in head in strict mode ? function(){ 'use strict'; try { eval('for (var i = 0 in {}) {}'); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
accessors aren't constructors ? function(){ var f = (Object.getOwnPropertyDescriptor({get a(){}}, 'a')).get; try { new f; } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
Invalid Date ? function(){ return new Date(NaN) + "" === "Invalid Date"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
RegExp constructor can alter flags ? function(){ return new RegExp(/./im, "g").global === true; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
RegExp.prototype.toString generic and uses "flags" property ? function(){ return RegExp.prototype.toString.call({source: 'foo', flags: 'bar'}) === '/foo/bar'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
built-in prototypes are not instances ? function(){ try { RegExp.prototype.exec(); return false; } catch(e) {} try { Date.prototype.valueOf(); return false; } catch(e) {} if (![Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError, URIError].every(function (E) { return Object.prototype.toString.call(E.prototype) === '[object Object]'; })) { return false; } return true; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
function 'length' is configurable ? function(){ var fn = function(a, b) {}; var desc = Object.getOwnPropertyDescriptor(fn, "length"); if (desc.configurable) { Object.defineProperty(fn, "length", { value: 1 }); return fn.length === 1; } return false; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No

##
annex b

### non-strict function semantics
hoisted block-level function declaration ? function(){ // Note: only available outside of strict mode. if (!this) return false; var passed = f() === 1; function f() { return 1; } passed &= typeof g === 'undefined'; { function g() { return 1; } } passed &= g() === 1; passed &= h() === 2; { function h() { return 1; } } function h() { return 2; } passed &= h() === 1; return passed; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
labeled function statements ? function(){ // Note: only available outside of strict mode. if (!this) return false; label: function foo() { return 2; } return foo() === 2; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
function statements in if-statement clauses ? function(){ // Note: only available outside of strict mode. if (!this) return false; if(true) function foo() { return 2; } if(false) {} else function bar() { return 3; } if(true) function baz() { return 4; } else {} if(false) function qux() { return 5; } else function qux() { return 6; } return foo() === 2 && bar() === 3 && baz() === 4 && qux() === 6; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### __proto__ in object literals
basic support ? function(){ return { __proto__ : [] } instanceof Array && !({ __proto__ : null } instanceof Object); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
multiple __proto__ is an error ? function(){ try { eval("({ __proto__ : [], __proto__: {} })"); } catch(e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
not a computed property ? function(){ if (!({ __proto__ : [] } instanceof Array)) { return false; } var a = "__proto__"; return !({ [a] : [] } instanceof Array); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
not a shorthand property ? function(){ if (!({ __proto__ : [] } instanceof Array)) { return false; } var __proto__ = []; return !({ __proto__ } instanceof Array); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | No No
not a shorthand method ? function(){ if (!({ __proto__ : [] } instanceof Array)) { return false; } return !({ __proto__(){} } instanceof Function); } | Error Error | Error Error | No No | No No | No No | No No | No Flag | No Flag | No Flag | Yes Yes
### Object.prototype.__proto__
get prototype ? function(){ var A = function(){}; return (new A()).__proto__ === A.prototype; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
set prototype ? function(){ var o = {}; o.__proto__ = Array.prototype; return o instanceof Array; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
absent from Object.create(null) ? function(){ var o = Object.create(null), p = {}; o.__proto__ = p; return Object.getPrototypeOf(o) !== p; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
present in hasOwnProperty() ? function(){ return Object.prototype.hasOwnProperty('__proto__'); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
correct property descriptor ? function(){ var desc = Object.getOwnPropertyDescriptor(Object.prototype,"__proto__"); var A = function(){}; return (desc && "get" in desc && "set" in desc && desc.configurable && !desc.enumerable); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
present in Object.getOwnPropertyNames() ? function(){ return Object.getOwnPropertyNames(Object.prototype).indexOf('__proto__') > -1; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
### String.prototype HTML methods
existence ? function(){ var i, names = ["anchor", "big", "bold", "fixed", "fontcolor", "fontsize", "italics", "link", "small", "strike", "sub", "sup"]; for (i = 0; i < names.length; i++) { if (typeof String.prototype[names[i]] !== 'function') { return false; } } return true; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
tags' names are lowercase ? function(){ var i, names = ["anchor", "big", "bold", "fixed", "fontcolor", "fontsize", "italics", "link", "small", "strike", "sub", "sup"]; for (i = 0; i < names.length; i++) { if (""[names[i]]().toLowerCase() !== ""[names[i]]()) { return false; } } return true; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
quotes in arguments are escaped ? function(){ var i, names = ["anchor", "fontcolor", "fontsize", "link"]; for (i = 0; i < names.length; i++) { if (""[names[i]]('"') !== ""[names[i]]('&' + 'quot;')) { return false; } } return true; } | No No | No No | No No | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
### RegExp.prototype.compile
basic functionality ? function(){ if (typeof RegExp.prototype.compile !== 'function') return false var rx = /a/; rx.compile('b'); return rx.test('b'); } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
returns this ? function(){ var rx = /a/; return rx.compile('b') === rx; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### RegExp syntax extensions
hyphens in character sets ? function(){ return /[\w-_]/.exec("-")[0] === "-"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
invalid character escapes ? function(){ return /\z/.exec("\\z")[0] === "z" && /[\z]/.exec("[\\z]")[0] === "z"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
invalid control-character escapes ? function(){ return /\c2/.exec("\\c2")[0] === "\\c2"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
invalid Unicode escapes ? function(){ return /\u1/.exec("u1")[0] === "u1" && /[\u1]/.exec("u")[0] === "u"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
invalid hexadecimal escapes ? function(){ return /\x1/.exec("x1")[0] === "x1" && /[\x1]/.exec("x")[0] === "x"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
incomplete patterns and quantifiers ? function(){ return /x{1/.exec("x{1")[0] === "x{1" && /x]1/.exec("x]1")[0] === "x]1"; } | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
octal escape sequences ? function(){ return /\041/.exec("!")[0] === "!" && /[\041]/.exec("!")[0] === "!"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
invalid backreferences become octal escapes ? function(){ return /\41/.exec("!")[0] === "!" && /[\41]/.exec("!")[0] === "!"; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
###
HTML-style comments ? function(){ --> A comment <!-- Another comment var a = 3; <!-- Another comment return a === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

# Rhino ES2016 Support

1.7R4 (these versions have identical results)
0% complete0% complete | 1.7R5 (these versions have identical results)
0% complete0% complete | 1.7.7.2 (these versions have identical results)
0% complete0% complete | 1.7.10 (these versions have identical results)
0% complete0% complete | 1.7.11 (these versions have identical results)
7% complete7% complete | 1.7.12 (these versions have identical results)
14% complete14% complete | 1.7.13 (these versions have identical results)
21% complete14% complete | 1.7.14 (these versions have identical results)
50% complete21% complete | 1.7.15 (these versions have identical results)
50% complete21% complete | 1.8.0 (these versions have identical results)
71% complete71% complete
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---

##
features

### exponentiation (**) operator
basic support ? function(){ return 2 ** 3 === 8 && -(5 ** 2) === -25 && (-5) ** 2 === 25; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
assignment ? function(){ var a = 2; a **= 3; return a === 8; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
early syntax error for unary negation without parens ? function(){ if (2 ** 3 !== 8) { return false; } try { Function ("-5 ** 2")(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
### Array.prototype.includes
Array.prototype.includes ? function(){ return [1, 2, 3].includes(1) && ![1, 2, 3].includes(4) && ![1, 2, 3].includes(1, 1) && [NaN].includes(NaN); } | Error Error | Error Error | Error Error | Error Error | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.includes handles sparse arrays ? function(){ return [,].includes() && Array(1).includes(); } | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
Array.prototype.includes is generic ? function(){ var passed = 0; return [].includes.call( { get "0"() { passed = NaN; return 'foo'; }, get "11"() { passed += 1; return 0; }, get "19"() { passed += 1; return 'foo'; }, get "21"() { passed = NaN; return 'foo'; }, get length() { passed += 1; return 24; } }, 'foo', 6 ) === true && passed === 3; } | Error Error | Error Error | Error Error | Error Error | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes
%TypedArray%.prototype.includes ? function(){ return [ Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, Float32Array, Float64Array ].every(function (TypedArray) { return new TypedArray([1, 2, 3]).includes(1) && !new TypedArray([1, 2, 3]).includes(4) && !new TypedArray([1, 2, 3]).includes(1, 1); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes

##
misc

###
generator functions can't be used with "new" ? function(){ function * generator() { yield 3; } try { new generator(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error No | Error No | Error No | No No
generator throw() caught by inner generator ? function(){ function * generator() { yield * (function * () { try { yield 'foo'; } catch (e) { return; } }()); yield 'bar'; } var iter = generator(); iter.next(); return iter['throw']().value === 'bar'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Error Flag | Yes Yes
strict fn w/ non-strict non-simple params is error ? function(){ function foo(...a) {} try { Function ("function bar(...a) {'use strict';}")(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No | No No
nested rest destructuring, declarations ? function(){ var [x, ...[y, ...z]] = [1,2,3,4]; return x === 1 && y === 2 && z + '' === '3,4'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
nested rest destructuring, parameters ? function(){ return function ([x, ...[y, ...z]]) { return x === 1 && y === 2 && z + '' === '3,4'; }([1,2,3,4]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Proxy, "enumerate" handler removed ? function(){ var passed = true; var proxy = new Proxy({}, { enumerate: function () { passed = false; } }); for (var key in proxy); // Should not throw, nor execute the 'enumerate' method. return passed; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
Proxy internal calls, Array.prototype.includes ? function(){ // Array.prototype.includes -> Get -> [[Get]] var get = []; var p = new Proxy({length: 3, 0: '', 1: '', 2: '', 3: ''}, { get: function (o, k) { get.push(k); return o[k]; }}); Array.prototype.includes.call(p, {}); if (get + '' !== "length,0,1,2") return; get = []; p = new Proxy({length: 4, 0: NaN, 1: '', 2: NaN, 3: ''}, { get: function (o, k) { get.push(k); return o[k]; }}); Array.prototype.includes.call(p, NaN, 1); return (get + '' === "length,1,2"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes

# Rhino ES2017 Support

1.7R4 (these versions have identical results)
14% complete14% complete | 1.7R5 (these versions have identical results)
14% complete14% complete | 1.7.7.2 (these versions have identical results)
14% complete14% complete | 1.7.10 (these versions have identical results)
14% complete14% complete | 1.7.11 (these versions have identical results)
21% complete21% complete | 1.7.12 (these versions have identical results)
21% complete21% complete | 1.7.13 (these versions have identical results)
21% complete21% complete | 1.7.14 (these versions have identical results)
25% complete21% complete | 1.7.15 (these versions have identical results)
28% complete25% complete | 1.8.0 (these versions have identical results)
29% complete29% complete
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---

##
features

### Object static methods
Object.values ? function(){ var obj = Object.create({ a: "qux", d: "qux" }); obj.a = "foo"; obj.b = "bar"; obj.c = "baz"; var v = Object.values(obj); return Array.isArray(v) && String(v) === "foo,bar,baz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Object.entries ? function(){ var obj = Object.create({ a: "qux", d: "qux" }); obj.a = "foo"; obj.b = "bar"; obj.c = "baz"; var e = Object.entries(obj); return Array.isArray(e) && e.length === 3 && String(e[0]) === "a,foo" && String(e[1]) === "b,bar" && String(e[2]) === "c,baz"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
Object.getOwnPropertyDescriptors ? function(){ var object = {a: 1}; var B = typeof Symbol === 'function' ? Symbol('b') : 'b'; object[B] = 2; var O = Object.defineProperty(object, 'c', {value: 3}); var D = Object.getOwnPropertyDescriptors(O); return D.a.value === 1 && D.a.enumerable === true && D.a.configurable === true && D.a.writable === true && D[B].value === 2 && D[B].enumerable === true && D[B].configurable === true && D[B].writable === true && D.c.value === 3 && D.c.enumerable === false && D.c.configurable === false && D.c.writable === false; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
Object.getOwnPropertyDescriptors doesn't provide undefined descriptors ? function(){ var P = new Proxy({ a: 1 }, { getOwnPropertyDescriptor: function (t, k) {} }); return !Object.getOwnPropertyDescriptors(P).hasOwnProperty('a'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
### String padding
String.prototype.padStart ? function(){ return 'hello'.padStart(10) === ' hello' && 'hello'.padStart(10, '1234') === '12341hello' && 'hello'.padStart() === 'hello' && 'hello'.padStart(6, '123') === '1hello' && 'hello'.padStart(3) === 'hello' && 'hello'.padStart(3, '123') === 'hello'; } | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
String.prototype.padEnd ? function(){ return 'hello'.padEnd(10) === 'hello ' && 'hello'.padEnd(10, '1234') === 'hello12341' && 'hello'.padEnd() === 'hello' && 'hello'.padEnd(6, '123') === 'hello1' && 'hello'.padEnd(3) === 'hello' && 'hello'.padEnd(3, '123') === 'hello'; } | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### trailing commas in function syntax
in parameter lists ? function(){ return typeof function f( a, b, ) {} === 'function'; } | No No | No No | No No | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
in argument lists ? function(){ return Math.min(1,2,3,) === 1; } | No No | No No | No No | Error Error | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### async functions
return ? function(){ async function a() { return "foo"; } var p = a(); if (!(p instanceof Promise)) { return false; } p.then(function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
throw ? function(){ async function a() { throw "foo"; } var p = a(); if (!(p instanceof Promise)) { return false; } p.catch (function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
no line break between async and function ? function(){ async function a() {} try { Function ("async\n function a() {await 0}")(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
no "prototype" property ? function(){ async function a() {}; return !a.hasOwnProperty("prototype"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
await ? function(){ (async function () { await Promise.resolve(); var a1 = await new Promise(function (resolve) { setTimeout(resolve,800,"foo"); }); var a2 = await new Promise(function (resolve) { setTimeout(resolve,800,"bar"); }); if (a1 + a2 === "foobar") { asyncTestPassed(); } }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
await, rejection ? function(){ (async function () { await Promise.resolve(); try { var a1 = await new Promise(function (_, reject) { setTimeout(reject,800,"foo"); }); } catch (e) { if (e === "foo") { asyncTestPassed(); } } }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
must await a value ? function(){ async function a() { await Promise.resolve(); } try { Function ("(async function a() { await; }())")(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
can await non-Promise values ? function(){ (async function () { await Promise.resolve(); var e = await "foo"; if (e === "foo") { asyncTestPassed(); } }()); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
cannot await in parameters ? function(){ async function a() { await Promise.resolve(); } try { Function ("(async function a(b = await Promise.resolve()) {}())")(); } catch (e) { return true; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async methods, object literals ? function(){ var o = { async a() { return await Promise.resolve("foo"); } }; var p = o.a(); if (!(p instanceof Promise)) { return false; } p.then(function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async methods, classes ? function(){ class C { async a() { return await Promise.resolve("foo"); } }; var p = new C().a(); if (!(p instanceof Promise)) { return false; } p.then(function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async arrow functions in methods, classes ? function(){ function doSomething(callback) { callback(); } class C { a() { doSomething(async () => { await 1; asyncTestPassed(); }); } }; var p = new C().a(); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async arrow functions ? function(){ var a = async () => await Promise.resolve("foo"); var p = a(); if (!(p instanceof Promise)) { return false; } p.then(function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
correct prototype chain ? function(){ var asyncFunctionProto = Object.getPrototypeOf(async function () {}); return asyncFunctionProto !== function () {}.prototype && Object.getPrototypeOf(asyncFunctionProto) === Function.prototype; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async function prototype, Symbol.toStringTag ? function(){ return Object.getPrototypeOf(async function () {})[Symbol.toStringTag] === "AsyncFunction"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
async function constructor ? function(){ var a = async function () {}.constructor("return 'foo';"); var p = a(); if (!(p instanceof Promise)) { return false; } p.then(function (result) { if (result === "foo") { asyncTestPassed(); } }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### shared memory and atomics
SharedArrayBuffer ? function(){ return typeof SharedArrayBuffer === 'function'; } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
SharedArrayBuffer[Symbol.species] ? function(){ return SharedArrayBuffer[Symbol.species] === SharedArrayBuffer; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
SharedArrayBuffer.prototype.byteLength ? function(){ return 'byteLength' in SharedArrayBuffer.prototype; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
SharedArrayBuffer.prototype.slice ? function(){ return typeof SharedArrayBuffer.prototype.slice === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
SharedArrayBuffer.prototype[Symbol.toStringTag] ? function(){ return SharedArrayBuffer.prototype[Symbol.toStringTag] === 'SharedArrayBuffer'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.add ? function(){ return typeof Atomics.add === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.and ? function(){ return typeof Atomics.and === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.compareExchange ? function(){ return typeof Atomics.compareExchange === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.exchange ? function(){ return typeof Atomics.exchange === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.wait ? function(){ return typeof Atomics.wait === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.notify ? function(){ return typeof Atomics.notify === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.isLockFree ? function(){ return typeof Atomics.isLockFree === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.load ? function(){ return typeof Atomics.load === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.or ? function(){ return typeof Atomics.or === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.store ? function(){ return typeof Atomics.store === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.sub ? function(){ return typeof Atomics.sub === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Atomics.xor ? function(){ return typeof Atomics.xor === 'function'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
misc

###
RegExp "u" flag, case folding ? function(){ return "ſ".match(/\w/iu) && !"ſ".match(/\W/iu) && "\u212a".match(/\w/iu) && !"\u212a".match(/\W/iu) && "\u212a".match(/.\b/iu) && "ſ".match(/.\b/iu) && !"\u212a".match(/.\B/iu) && !"ſ".match(/.\B/iu); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
arguments.caller removed ? function(){ return (function () { 'use strict'; return !Object.getOwnPropertyDescriptor(arguments, 'caller'); })(); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No

##
annex b

### Object.prototype getter/setter methods
__defineGetter__ ? function(){ var obj = {}; function bar() { return "bar"; } Object.prototype.__defineGetter__.call(obj, "foo", bar); var prop = Object.getOwnPropertyDescriptor(obj, "foo"); return prop.get === bar && !prop.writable && prop.configurable && prop.enumerable; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__defineGetter__, symbols ? function(){ var obj = {}; var sym = Symbol(); function bar() { return "bar"; } Object.prototype.__defineGetter__.call(obj, sym, bar); var prop = Object.getOwnPropertyDescriptor(obj, sym); return prop.get === bar && !prop.writable && prop.configurable && prop.enumerable; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
__defineGetter__, ToObject(this) ? function(){ var key = '__accessors_test__'; __defineGetter__.call(1, key, function () {}); try { __defineGetter__.call(null, key, function () {}); } catch (e) { return true; } } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__defineSetter__ ? function(){ var obj = {}; function bar() {} Object.prototype.__defineSetter__.call(obj, "foo", bar); var prop = Object.getOwnPropertyDescriptor(obj, "foo"); return prop.set === bar && !prop.writable && prop.configurable && prop.enumerable; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__defineSetter__, symbols ? function(){ var obj = {}; var sym = Symbol(); function bar(baz) {} Object.prototype.__defineSetter__.call(obj, sym, bar); var prop = Object.getOwnPropertyDescriptor(obj, sym); return prop.set === bar && !prop.writable && prop.configurable && prop.enumerable; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
__defineSetter__, ToObject(this) ? function(){ var key = '__accessors_test__'; __defineSetter__.call(1, key, function () {}); try { __defineSetter__.call(null, key, function () {}); } catch (e) { return true; } } | No No | No No | No No | No No | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupGetter__ ? function(){ var obj = { get foo() { return "bar"}, qux: 1 }; var foo = Object.prototype.__lookupGetter__.call(obj, "foo"); return foo() === "bar" && Object.prototype.__lookupGetter__.call(obj, "qux") === void undefined && Object.prototype.__lookupGetter__.call(obj, "baz") === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupGetter__, prototype chain ? function(){ var obj = { get foo() { return "bar"}, qux: 1 }; var foo = Object.prototype.__lookupGetter__.call(Object.create(obj), "foo"); return foo() === "bar" && Object.prototype.__lookupGetter__.call(obj, "qux") === void undefined && Object.prototype.__lookupGetter__.call(obj, "baz") === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupGetter__, symbols ? function(){ var sym = Symbol(); var sym2 = Symbol(); var obj = {}; Object.defineProperty(obj, sym, { get: function () { return "bar"; }}); Object.defineProperty(obj, sym2, { value: 1 }); var foo = Object.prototype.__lookupGetter__.call(obj, sym); return foo() === "bar" && Object.prototype.__lookupGetter__.call(obj, sym2) === void undefined && Object.prototype.__lookupGetter__.call(obj, Symbol()) === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
__lookupGetter__, ToObject(this) ? function(){ __lookupGetter__.call(1, 'key'); try { __lookupGetter__.call(null, 'key'); } catch (e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
__lookupGetter__, data properties can shadow accessors ? function(){ var a = {}; var b = Object.create(a); b.foo = 1; a.__defineGetter__("foo", function () {}); return b.__lookupGetter__("foo") === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupSetter__ ? function(){ var obj = { set foo(baz) { return "bar"; }, qux: 1 }; var foo = Object.prototype.__lookupSetter__.call(obj, "foo"); return foo() === "bar" && Object.prototype.__lookupSetter__.call(obj, "qux") === void undefined && Object.prototype.__lookupSetter__.call(obj, "baz") === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupSetter__, prototype chain ? function(){ var obj = { set foo(baz) { return "bar"; }, qux: 1 }; var foo = Object.prototype.__lookupSetter__.call(Object.create(obj), "foo"); return foo() === "bar" && Object.prototype.__lookupSetter__.call(obj, "qux") === void undefined && Object.prototype.__lookupSetter__.call(obj, "baz") === void undefined; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
__lookupSetter__, symbols ? function(){ var sym = Symbol(); var sym2 = Symbol(); var obj = {}; Object.defineProperty(obj, sym, { set: function (baz) { return "bar"; }}); Object.defineProperty(obj, sym2, { value: 1 }); var foo = Object.prototype.__lookupSetter__.call(obj, sym); return foo() === "bar" && Object.prototype.__lookupSetter__.call(obj, sym2) === void undefined && Object.prototype.__lookupSetter__.call(obj, Symbol()) === void undefined; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
__lookupSetter__, ToObject(this) ? function(){ __lookupSetter__.call(1, 'key'); try { __lookupSetter__.call(null, 'key'); } catch (e) { return true; } } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No
__lookupSetter__, data properties can shadow accessors ? function(){ var a = {}; var b = Object.create(a); b.foo = 1; a.__defineSetter__("foo", function () {}) return b.__lookupSetter__("foo") === void undefined } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
### Proxy internal calls, getter/setter methods
__defineGetter__ ? function(){ // Object.prototype.__defineGetter__ -> DefinePropertyOrThrow -> [[DefineOwnProperty]] var def = []; var p = new Proxy({}, { defineProperty: function (o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; } }); Object.prototype.__defineGetter__.call(p, "foo", Object); return def + '' === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
__defineSetter__ ? function(){ // Object.prototype.__defineSetter__ -> DefinePropertyOrThrow -> [[DefineOwnProperty]] var def = []; var p = new Proxy({}, { defineProperty: function (o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; } }); Object.prototype.__defineSetter__.call(p, "foo", Object); return def + '' === "foo"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
__lookupGetter__ ? function(){ // Object.prototype.__lookupGetter__ -> [[GetOwnProperty]] // Object.prototype.__lookupGetter__ -> [[GetPrototypeOf]] var gopd = []; var gpo = false; var p = new Proxy({}, { getPrototypeOf: function (o) { gpo = true; return Object.getPrototypeOf(o); }, getOwnPropertyDescriptor: function (o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); } }); Object.prototype.__lookupGetter__.call(p, "foo"); return gopd + '' === "foo" && gpo; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
__lookupSetter__ ? function(){ // Object.prototype.__lookupSetter__ -> [[GetOwnProperty]] // Object.prototype.__lookupSetter__ -> [[GetPrototypeOf]] var gopd = []; var gpo = false; var p = new Proxy({}, { getPrototypeOf: function (o) { gpo = true; return Object.getPrototypeOf(o); }, getOwnPropertyDescriptor: function (o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); } }); Object.prototype.__lookupSetter__.call(p, "foo"); return gopd + '' === "foo" && gpo; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | No No
###
assignments allowed in for-in head in non-strict mode ? function(){ for (var i = 0 in {}) {} return i === 0; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes

# Rhino ES2018 Support

1.7R4 (these versions have identical results)
0% complete0% complete | 1.7R5 (these versions have identical results)
0% complete0% complete | 1.7.7.2 (these versions have identical results)
0% complete0% complete | 1.7.10 (these versions have identical results)
0% complete0% complete | 1.7.11 (these versions have identical results)
0% complete0% complete | 1.7.12 (these versions have identical results)
0% complete0% complete | 1.7.13 (these versions have identical results)
0% complete0% complete | 1.7.14 (these versions have identical results)
19% complete4% complete | 1.7.15 (these versions have identical results)
23% complete9% complete | 1.8.0 (these versions have identical results)
28% complete28% complete
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---

##
features

### object rest/spread properties
object rest properties ? function(){ var { a, ...rest } = { a: 1, b: 2, c: 3 }; return a === 1 && rest.a === void undefined && rest.b === 2 && rest.c === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
object spread properties ? function(){ var spread = { b: 2, c: 3 }; var O = { a: 1, ...spread }; return O !== spread && (O.a + O.b + O.c) === 6; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Promise.prototype.finally
basic support ? function(){ var p1 = Promise.resolve("foo"); var p2 = Promise.reject("bar"); var score = 0; function thenFn(result) { score += (result === "foo"); check(); } function catchFn(result) { score += (result === "bar"); check(); } function finallyFn() { score += (arguments.length === 0); check(); } p1.then(thenFn); p1.finally(finallyFn); p1.finally(function () { // should return a new Promise score += p1.finally() !== p1; check(); }); p2.catch (catchFn); p2.finally(finallyFn); function check() { if (score === 5) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
don't change resolution value ? function(){ var score = 0; function thenFn(result) { score += (result === "foo"); check(); } function catchFn(result) { score += (result === "bar"); check(); } function finallyFn() { score++; check(); return Promise.resolve("foobar"); } Promise.resolve("foo").finally(finallyFn).then(thenFn); Promise.reject("bar").finally(finallyFn).catch(catchFn); function check() { if (score === 4) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
change rejection value ? function(){ var score = 0; Promise .reject("foobar") .finally(function () { return Promise.reject("foo"); }) .catch (function (result) { score += (result === "foo"); check(); return Promise.reject("foobar"); }) .finally(function () { throw new Error('bar'); }) .catch (function (result) { score += (result.message === "bar"); check(); }); function check() { if (score === 2) asyncTestPassed(); } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Flag | Error Flag | Yes Yes
###
s (dotAll) flag for regular expressions ? function(){ const regex = /foo.bar/s; return regex.test('foo\nbar'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes
RegExp named capture groups ? function(){ var result = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/.exec('2016-03-11'); return result.groups.year === '2016' && result.groups.month === '03' && result.groups.day === '11' && result[0] === '2016-03-11' && result[1] === '2016' && result[2] === '03' && result[3] === '11'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
RegExp Lookbehind Assertions ? function(){ return /(?<=a)b/.test('ab') && /(?<!a)b/.test('cb') && !/(?<=a)b/.test('b'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### RegExp Unicode Property Escapes
basic ? function(){ const regexGreekSymbol = /\p{Script=Greek}/u; return regexGreekSymbol.test('π'); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 11 ? function(){ return /\p{Extended_Pictographic}/u.test("\xA9") && /\p{Emoji}/u.test("🥰"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 12 ? function(){ return /\p{Script=Elymaic}/u.test("\u{10fe0}") && /\p{Emoji}/u.test("🥱"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 12.1 ? function(){ return /\p{Other_Symbol}/u.test("\u32FF"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 13 ? function(){ return /\p{Script=Chorasmian}/u.test("\u{10fb0}") && /\p{Emoji}/u.test("🥲"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 14 ? function(){ return /\p{Script=Vithkuqi}/u.test("\u{10570}") && /\p{Emoji}/u.test("🫠"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 15 ? function(){ return /\p{Script=Kawi}/u.test("\u{11f00}") && /\p{Emoji}/u.test("🫨"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 15.1 ? function(){ return /\p{Unified_Ideograph}/u.test("\u{2ebf0}"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Unicode 16.0 ? function(){ return /\p{Script=Todhri}/u.test("\u{105c0}") && /\p{Emoji}/u.test("🫩"); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Asynchronous Iterators
async generators ? function(){ async function*generator() { yield 42; } var iterator = generator(); iterator.next().then(function (step) { if(iterator[Symbol.asyncIterator]() === iterator && step.done === false && step.value === 42)asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
for-await-of loops ? function(){ var asyncIterable = {}; asyncIterable[Symbol.asyncIterator] = function () { var i = 0; return { next: function () { switch(++i) { case 1: return Promise.resolve({done: false, value: 'a'}); case 2: return Promise.resolve({done: false, value: 'b'}); } return Promise.resolve({done: true}); } }; }; (async function () { var result = ''; for await(var value of asyncIterable)result += value; if(result === 'ab')asyncTestPassed(); })(); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
misc

###
Proxy "ownKeys" handler, duplicate keys for non-extensible targets ? function(){ var p = new Proxy({}, { ownKeys() { return ["a", "a"]; } }); try { Object.keys(p); } catch (e) { return e instanceof TypeError; } return false; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes
template literal revision ? function(){ function tag(strings, a) { return strings[0] === void undefined && strings.raw[0] === "\\01\\1\\xg\\xAg\\u0\\u0g\\u00g\\u000g\\u{g\\u{0\\u{110000}" && strings[1] === "\0" && strings.raw[1] === "\\0" && a === 0; } return tag`\01\1\xg\xAg\u0\u0g\u00g\u000g\u{g\u{0\u{110000}${0}\0`; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Yes Yes | Yes Yes | Yes Yes

# Rhino ESNEXT Support

1.7R4 (these versions have identical results)
5% complete5% complete | 1.7R5 (these versions have identical results)
5% complete5% complete | 1.7.7.2 (these versions have identical results)
5% complete5% complete | 1.7.10 (these versions have identical results)
5% complete5% complete | 1.7.11 (these versions have identical results)
5% complete5% complete | 1.7.12 (these versions have identical results)
5% complete5% complete | 1.7.13 (these versions have identical results)
5% complete5% complete | 1.7.14 (these versions have identical results)
5% complete5% complete | 1.7.15 (these versions have identical results)
5% complete5% complete | 1.8.0 (these versions have identical results)
5% complete5% complete
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---

##
Stage 3

### Class and Property Decorators
class decorators ? function(){ class A { @nonconf get B() {} } function nonconf(target, name, descriptor) { descriptor.configurable = false; return descriptor; } return Object.getOwnPropertyDescriptor(A.prototype, "B").configurable === false; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Legacy RegExp features in JavaScript
RegExp "lastMatch" ? function(){ var re = /\w/; re.exec('x'); return RegExp.lastMatch === 'x'; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
RegExp.$1-$9 ? function(){ for (var i = 1; i < 10; i++) { if (!(('$' + i) in RegExp)) return false; } return true; } | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes | Yes Yes
###
RegExp Escaping ? function(){ return RegExp.escape("The Quick Brown Fox") === "The\\ Quick\\ Brown\\ Fox" && RegExp.escape("(*.*)") === "\\(\\*\\.\\*\\)" && RegExp.escape("｡^･ｪ･^｡") === "｡\\^･ｪ･\\^｡" && RegExp.escape("\\d \\D (?:)") === "\\\\d \\\\D \\(\\?\\:\\)"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Uint8Array to/from base64 and hex
Uint8Array.toBase64() ? function(){ const arr = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); return arr.toBase64() === "SGVsbG8gV29ybGQ="; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Uint8Array.fromBase64() ? function(){ const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); const arr2 = Uint8Array.fromBase64("SGVsbG8gV29ybGQ="); return arr1.length === arr2.length && arr1.every((element, index) => element === arr2[index]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Uint8Array.setFromBase64() ? function(){ const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); let arr2 = new Uint8Array(16); let { read, written } = arr2.setFromBase64("SGVsbG8gV29ybGQ="); return read == 16 && written == 11 && arr1.every((element, index) => element === arr2[index]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Uint8Array.toHex() ? function(){ const arr = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); return arr.toHex() === "48656c6c6f20576f726c64"; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Uint8Array.fromHex() ? function(){ const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); const arr2 = Uint8Array.fromHex("48656c6c6f20576f726c64"); return arr1.length === arr2.length && arr1.every((element, index) => element === arr2[index]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Uint8Array.setFromHex() ? function(){ const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]); let arr2 = new Uint8Array(16); let { read, written } = arr2.setFromHex("48656c6c6f20576f726c64"); return read == 22 && written == 11 && arr1.every((element, index) => element === arr2[index]); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error

##
Stage 2.7

###
ShadowRealm ? function(){ return typeof ShadowRealm === "function" && ["evaluate", "importValue"].every(function(key){ return key in ShadowRealm.prototype; }); } | No No | No No | No No | No No | No No | No No | No No | No No | No No | No No

##
Stage 2

###
Generator function.sent Meta Property ? function(){ var result; function* generator() { result = function.sent; } var iter = generator(); iter.next('tromple'); return result === 'tromple'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
Array.isTemplateObject ? function(){ return !Array.isTemplateObject([]) && Array.isTemplateObject((it => it)`a${1}c`); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### throw expressions
logical ? function(){ var a, b; try { a = 19 || throw 77; b = 88 && throw 23; } catch (e) { return a + e === 42; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
parameter initializers ? function(){ function fn (arg = throw 42) { return arg; } if (fn(21) !== 21) return false; try { fn(); } catch (e) { return e === 42; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
arrow function bodies ? function(){ var fn = () => throw 42; try { fn(); } catch (e) { return e === 42; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
conditionals ? function(){ true ? 42 : throw 21; try { false ? 42 : throw 21; } catch (e) { return e === 21; } } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Map.prototype.upsert
Map.prototype.upsert ? function(){ const map = new Map([['a', 1]]); if (map.upsert('a', it => 2, () => 3) !== 2) return false; if (map.upsert('b', it => 2, () => 3) !== 3) return false; return Array.from(map).join() === 'a,2,b,3'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
WeakMap.prototype.upsert ? function(){ const a = {}, b = {}; const map = new WeakMap([[a, 1]]); if (map.upsert(a, it => 2, () => 3) !== 2) return false; if (map.upsert(b, it => 2, () => 3) !== 3) return false; return map.get(a) === 2 && map.get(b) === 3; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
### Async Iterator Helpers
instanceof AsyncIterator ? function(){ return (async function*() {})() instanceof AsyncIterator; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
extends AsyncIterator ? function(){ class Class extends AsyncIterator { } const instance = new Class(); return instance[Symbol.asyncIterator]() === instance; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.from, async iterable ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } const iterator = AsyncIterator.from(async function*() { yield * [1, 2, 3] }()); if (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false; toArray(iterator).then(it => { if (it.join() === '1,2,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.from, iterable ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } const iterator = AsyncIterator.from([1, 2, 3]); if (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false; toArray(iterator).then(it => { if (it.join() === '1,2,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.from, iterator ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } const iterator = AsyncIterator.from([1, 2, 3].values()); if (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false; toArray(iterator).then(it => { if (it.join() === '1,2,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.drop ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } toArray(async function*() { yield * [1, 2, 3] }().drop(1)).then(it => { if (it.join() === '2,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.every ? function(){ (async function*() { yield * [1, 2, 3] })().every(it => typeof it === 'number').then(it => { if (it === true) asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.filter ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } toArray(async function*() { yield * [1, 2, 3] }().filter(it => it % 2)).then(it => { if (it.join() === '1,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.find ? function(){ (async function*() { yield * [1, 2, 3] })().find(it => it % 2).then(it => { if (it === 1) asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.flatMap ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } toArray(async function*() { yield * [1, 2, 3] }().flatMap(it => [it, 0])).then(it => { if (it.join() === '1,0,2,0,3,0') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.forEach ? function(){ let result = ''; (async function*() { yield * [1, 2, 3] })().forEach(it => result += it).then(() => { if (result === '123') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.map ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } toArray(async function*() { yield * [1, 2, 3] }().map(it => it * it)).then(it => { if (it.join() === '1,4,9') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.reduce ? function(){ (async function*() { yield * [1, 2, 3] })().reduce((a, b) => a + b).then(it => { if (it === 6) asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.some ? function(){ (async function*() { yield * [1, 2, 3] })().some(it => typeof it === 'number').then(it => { if (it === true) asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.take ? function(){ async function toArray(iterator) { const result = []; for await (const it of iterator) result.push(it); return result; } toArray(async function*() { yield * [1, 2, 3] }().take(2)).then(it => { if (it.join() === '1,2') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype.toArray ? function(){ (async function*() { yield * [1, 2, 3] })().toArray().then(it => { if (Array.isArray(it) && it.join() === '1,2,3') asyncTestPassed(); }); } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error
AsyncIterator.prototype[@@toStringTag] ? function(){ return AsyncIterator.prototype[Symbol.toStringTag] === 'AsyncIterator'; } | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error | Error Error