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The initial value of the @@iterator
property is the same function object as the initial value of the entries
property.
Syntax
myMap[Symbol.iterator]
Return value
The map iterator function, which is the entries()
function by default.
Examples
Using [@@iterator]()
var myMap = new Map(); myMap.set("0", "foo"); myMap.set(1, "bar"); myMap.set({}, "baz"); var mapIter = myMap[Symbol.iterator](); console.log(mapIter.next().value); // ["0", "foo"] console.log(mapIter.next().value); // [1, "bar"] console.log(mapIter.next().value); // [Object, "baz"]
Using [@@iterator]()
with for..of
var myMap = new Map(); myMap.set("0", "foo"); myMap.set(1, "bar"); myMap.set({}, "baz"); for (var v of myMap) { console.log(v); }
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Map.prototype[@@iterator]()' in that specification. |
Standard | Initial definition. |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Map.prototype[@@iterator]()' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | 36 (36) [1] | No support | No support | No support |
Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|
Basic support | No support | 36.0 (36) [1] | No support | No support | No support | (Yes) |
[1] From Gecko 17 (Firefox 17 / Thunderbird 17 / SeaMonkey 2.14) to Gecko 26 (Firefox 26 / Thunderbird 26 / SeaMonkey 2.23 / Firefox OS 1.2) the iterator
property was used (bug 907077), and from Gecko 27 to Gecko 35 the "@@iterator"
placeholder was used. In Gecko 36 (Firefox 36 / Thunderbird 36 / SeaMonkey 2.33), the @@iterator
symbol got implemented (bug 918828).