Promise ( Firefox 24, enabled by default in Firefox 29).Date.prototype is an ordinary object ( Firefox 41).Object.getOwnPropertySymbols() ( Firefox 33).Object.prototype._proto_ has been standardized.Number.MAX_SAFE_INTEGER, Number.MIN_SAFE_INTEGER ( Firefox 31).Constructor argument: new WeakSet(null) ( Firefox 37).Constructor argument: new WeakMap(null) ( Firefox 37).optional iterable argument in WeakMap constructor ( Firefox 36).

Monkey-patched add() in Constructor ( Firefox 37).Constructor argument: new Set(null) ( Firefox 37).Set iteration with for.of ( Firefox 17).

Monkey-patched set() in Constructor ( Firefox 37).Constructor argument: new Map(null) ( Firefox 37).Map iteration with for.of ( Firefox 17).New Map and Set objects, and their weak counterparts Array iteration with for.of ( Firefox 13).Standard library Additions to the Array object The features listed here are already supported in Firefox the version in which support was added is also indicated for each feature. It will also appear as the international industry standard ISO/IEC 16262:2016.Ī PDF and HTML version of the standard can be freely downloaded on .Ī channel for feedback on ECMAScript standards is es-discuss. Finally, ECMA-262 Edition 6 got officially approved and published as a standard on Jby the ECMA General Assembly. In August 2014, the ECMAScript 6 draft specification was feature frozen and went through a stabilization and bug fixing period. Commonly referred to as 'ES6', it defines the standard for the JavaScript implementation in SpiderMonkey, the engine used in Firefox and other Mozilla applications.Ĭode-named 'ES.next' or 'Harmony', the first working draft (based on ECMAScript 5.1) was published on Jas 'ES.next'. ECMAScript 2015 (6th Edition) is the current version of the ECMAScript Language Specification standard. Overview # class Point įor derived classes, the following default constructor is used: constructor(. The most significant recent changes were related to how subclassing is handled. This blog post explains how their final incarnation works.

Recently, TC39 decided on the final semantics of classes in ECMAScript 6.

Ecma 6