The initial value of the @@iterator
property is the same function object as the initial value of the entries
method.
Syntax
myMap[Symbol.iterator]
Return value
The map iterator function, which is the entries()
function by default.
Examples
Using [@@iterator]()
const myMap = new Map(); myMap.set('0', 'foo'); myMap.set(1, 'bar'); myMap.set({}, 'baz'); const 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
const myMap = new Map(); myMap.set('0', 'foo'); myMap.set(1, 'bar'); myMap.set({}, 'baz'); for (const entry of myMap) { console.log(entry); } // ["0", "foo"] // [1, "bar"] // [{}, "baz"] for (const [key, value] of myMap) { console.log(`${key}: ${value}`); } // 0: foo // 1: bar // [Object]: baz
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Map.prototype[@@iterator]()' in that specification. |
Standard | Initial definition. |
ECMAScript Latest Draft (ECMA-262) The definition of 'Map.prototype[@@iterator]()' in that specification. |
Living Standard |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | Yes | Yes | 17 — 271 364 | No | Yes | Yes |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | Yes | Yes | Yes | 17 — 271 364 | No | Yes | Yes |
1. Supported as iterator
.
2. A placeholder property named @@iterator
is used.
3. Supported as @@iterator
.
4. The @@iterator
symbol is implemented.