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Map.prototype[@@iterator]()

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).

See also

Document Tags and Contributors

 Contributors to this page: eduardoboucas, fscholz, jpmedley, arai
 Last updated by: eduardoboucas,