map.keys
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
myMap.keys()
返回值
一个新的Mapiterator 对象.
示例
使用 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
| 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 |
