@@iterator
属性的初始值与 entries
属性的初始值是同一个函数对象。
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语法
myMap[Symbol.iterator]
返回值
map 的 iterator 函数默认就是 entries()
函数。
示例
使用 [@@iterator]()
var myMap = new Map(); myMap.set('0', 'foo'); myMap.set(1, 'bar'); myMap.set({}, 'baz'); var mapIter = myMap[Symbol.iterator](); //返回的其实是个generator console.log(mapIter.next().value); // ["0", "foo"] console.log(mapIter.next().value); // [1, "bar"] console.log(mapIter.next().value); // [Object, "baz"]
在for..of中
使用[@@iterator]()
var 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 (var v of myMap) { console.log(v); } // 0: foo // 1: bar // [Object]: baz
规范
Specification | Status | Comment |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) Map.prototype[@@iterator]() |
Standard | Initial definition. |
ECMAScript Latest Draft (ECMA-262) Map.prototype[@@iterator]() |
Draft |
浏览器兼容
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.
Update compatibility data on GitHub
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
@@iterator |
Chrome Full support 43 | Edge Full support 12 | Firefox Full support 36
|
IE No support No | Opera Full support 30 | Safari Full support Yes | WebView Android Full support 43 | Chrome Android Full support 43 | Firefox Android Full support 36
|
Opera Android Full support 30 | Safari iOS Full support Yes | Samsung Internet Android Full support 4.0 | nodejs Full support 0.12 |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.
- See implementation notes.
- Uses a non-standard name.
- Uses a non-standard name.