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map.keys

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。

语法

代码语言:javascript
复制
myMap.keys()

返回值

一个新的Mapiterator 对象.

示例

使用 keys()

代码语言:javascript
复制
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

Specification

Status

Comment

ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'Map.prototype.keys' in that specification.

Standard

Initial definition.

ECMAScript Latest Draft (ECMA-262)The definition of 'Map.prototype.keys' in that specification.

Draft

?

浏览器兼容性

Feature

Chrome

Edge

Firefox (Gecko)

Internet Explorer

Opera

Safari

Basic support

38

(Yes)

20 (20)

No support

25

7.1

Feature

Android

Chrome for Android

Edge

Firefox Mobile (Gecko)

IE Mobile

Opera Mobile

Safari Mobile

Basic support

No support

38

(Yes)

20.0 (20)

No support

No support

8

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