Suporte ao ECMAScript 6 na Mozilla

ECMAScript 2015 is the next version of the standard, code-named "ES.next". Specification drafts can be found on the official ECMA wiki. The first working draft based on ECMAScript 5.1, was published on July 12, 2011 as "ES.next". As of August 2014, ECMAScript 2015 is already feature frozen, will be finished during 2015 and will start to go into the official publication process starting in March 2015 (to be finished in June 2015).

A channel for feedback on ECMAScript standards is es-discuss.

Recursos já suportados no Firefox

The following features are already implemented in Firefox:

Standard library

Adições para o objeto Array

• Array iteration with for...of (Firefox 13)
• Array.from() (Firefox 32)
• Array.of() (Firefox 25)
• Array.prototype.fill() (Firefox 31)
• Array.prototype.find(), Array.prototype.findIndex() (Firefox 25)
• Array.prototype.entries(),
  Array.prototype.keys() (Firefox 28)
• Array.prototype.copyWithin() (Firefox 32)

Novos objetos Map e Set, e seus weak counterparts

• Map (Firefox 13)
  • Map iteration with for...of (Firefox 17)
  • Map.prototype.forEach() (Firefox 25)
  • Map.prototype.entries(),
    Map.prototype.keys(),
    Map.prototype.values() (Firefox 20)
  • Constructor argument: new Map(null) (Firefox 37)
  • Monkey-patched set() in Constructor (Firefox 37)
• Set (Firefox 13)
  • Set iteration with for...of (Firefox 17)
  • Set.prototype.forEach() (Firefox 25)
  • Set.prototype.entries(),
    Set.prototype.keys(),
    Set.prototype.values() (Firefox 24)
  • Constructor argument: new Set(null) (Firefox 37)
  • Monkey-patched add() in Constructor (Firefox 37)
• WeakMap (Firefox 6)
  • WeakMap.clear() (Firefox 20)
  • optional iterable argument in WeakMap constructor (Firefox 36)
  • Constructor argument: new WeakMap(null) (Firefox 37)
  • Monkey-patched set() in Constructor (Firefox 37)
• WeakSet (Firefox 34)
  • Constructor argument: new WeakSet(null) (Firefox 37)
  • Monkey-patched add() in Constructor (Firefox 37)

Novas funções Math

• Math.imul() (Firefox 20)
• Math.clz32() (Firefox 31)
• Math.fround() (Firefox 26)
• Math.log10(), Math.log2(), Math.log1p(), Math.expm1(), Math.cosh(), Math.sinh(), Math.tanh(), Math.acosh(), Math.asinh(), Math.atanh(), Math.hypot(), Math.trunc(), Math.sign(), Math.cbrt() (Firefox 25)

Adições para o objeto Number

• Number.isNaN() (Firefox 16)
• Number.isFinite() (Firefox 16)
• Number.isInteger() (Firefox 16)
• Number.parseInt() (Firefox 25)
• Number.parseFloat() (Firefox 25)
• Number.EPSILON (Firefox 25)
• Number.MAX_SAFE_INTEGER, Number.MIN_SAFE_INTEGER (Firefox 31)
• Number.isSafeInteger() (Firefox 32)

Adições para o objeto Object

• Object.is() (Firefox 22)
• Object.setPrototypeOf() (Firefox 31)
• Object.assign() (Firefox 34)
• Object.getOwnPropertySymbols() (Firefox 33)

New Promise object

• Promise (Firefox 24, enabled by default in Firefox 29)

Adições para objeto RegExp

• RegExp sticky (y) flag (Firefox 3)
• generic RegExp.prototype.toString (Firefox 39)

Adições para objeto String

• String.fromCodePoint() (Firefox 29)
• String.prototype.codePointAt() (Firefox 29)
• String.prototype.startsWith(), String.prototype.endsWith() (Firefox 17)
• String.prototype.includes() (Firefox 17)
• String.prototype.repeat() (Firefox 24)
• String.prototype.normalize() (Firefox 31)
• String.raw() (Firefox 34)

New Symbol object

• Symbol (Firefox 36)
• Symbol.iterator (Firefox 36)
• Symbol.for() - global Symbol registry (Firefox 36)
• Symbol.match (Firefox 40)

Nova sintaxe de classe

• Basic support (Firefox 39)
• extends support (Firefox 39)
• static method definitions (Firefox 39)

Arrays tipados

Typed arrays are specified as part of ECMAScript 6 and no longer in their own specification.

• ArrayBuffer
• DataView
• Int8Array
• Uint8Array
• Uint8ClampedArray
• Int16Array
• Uint16Array
• Int32Array
• Uint32Array
• Float32Array
• Float64Array

Expressões e operadores

• Spread operator for arrays (Firefox 16)
  • use Symbol.iterator property (Firefox 36)
• Spread operator for function calls (Firefox 27)
  • use Symbol.iterator property (Firefox 36)

Statements

• for...of (Firefox 13)
  • works in terms of .iterator() and .next() (Firefox 17)
  • use "@@iterator" property (Firefox 27)
  • use Symbol.iterator property (Firefox 36)

Funções

• Rest parameters (Firefox 15)
• Default parameters (Firefox 15)
• Arrow functions (Firefox 22)
• Generator function (Firefox 26)
  • yield (Firefox 26)
  • yield* (Firefox 27)

Outros recursos

• Binary and octal numeric literals (Firefox 25)
• Template strings (Firefox 34)
• Object initializer: shorthand property names (Firefox 33)
• Object initializer: computed property names (Firefox 34)
• Object initializer: shorthand method names (Firefox 34)

Features with compliance and stabilization changes ongoing

Os seguintes recursos estão (parcialmente) implementados n Firefox, mas foram introduzidos muito antes do ES6 ou ainda estão sendo discutidos pela ECMA TC39 standards body.

• Legacy iterators and generators (JS 1.7, Firefox 2)
  • ES6 iterators and generators implemented in Firefox 26+
• Destructuring assignment (JS 1.7, Firefox 2) (ES6 compliance bug 950547)
• const (JS 1.5, Firefox 1.0) (ES6 compliance bug 950547)
• let (JS 1.7, Firefox 2) (ES6 compliance bug 950547)
• Proxy (Firefox 18) (ES6 compliance bug 978228)

Recursos ainda não suportados

Os seguintes recursos estão no rascunho da especificação ECMAScript 6, mas ainda não foram implementados no firefox:

• Modules (bug 568953)
  • import syntax
  • export syntax
• Array.prototype.values() (bug 875433)
• Reflect (bug 987514)
• \u{nnnnnn} Unicode code point escapes (bug 320500)
• Well-known symbols
• RegExp "u" flag

Veja também

• ECMAScript web site
• ECMAScript 2015 specification drafts
• Mozilla ES2015 tracking bug
• ECMAScript 2015 support across browsers