keys()
返回一个新的 Iterator
对象。它包含按照顺序插入 Map
对象中每个元素的key值。
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
myMap.keys()
一个新的 Map
iterator 对象.
keys()
var myMap = new Map();
myMap.set("0", "foo");
myMap.set(1, "bar");
myMap.set({}, "baz");
var mapIter = myMap.keys();
console.log(mapIter.next().value); // "0"
console.log(mapIter.next().value); // 1
console.log(mapIter.next().value); // Object
规范 | 状态 | 备注 |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) Map.prototype.keys |
Standard | Initial definition. |
ECMAScript Latest Draft (ECMA-262) Map.prototype.keys |
Draft |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
keys | Chrome Full support 38 | Edge Full support 12 | Firefox Full support 20 | IE No support No | Opera Full support 25 | Safari Full support 8 | WebView Android Full support 38 | Chrome Android Full support 38 | Edge Mobile Full support 12 | Firefox Android Full support 20 | Opera Android Full support 25 | Safari iOS Full support 8 | Samsung Internet Android Full support Yes | nodejs Full support 0.12 |