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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).