JS keys()
**keys()
**方法返回新的 Array Iterator
对象,包含数组中每个下标的键。
语法
arr.keys()
返回值
新的**Array Iterator**
对象
示例
使用for...of
循环的迭代
var arr = new Uint8Array([10, 20, 30, 40, 50]);
var eArray = arr.keys();
// 你的浏览器必须支持 for..of 循环
// 以及 for 循环中的 let 区域变量
for (let n of eArray) {
console.log(n);
}
备选的迭代
var arr = new Uint8Array([10, 20, 30, 40, 50]);
var eArr = arr.keys();
console.log(eArr.next().value); // 0
console.log(eArr.next().value); // 1
console.log(eArr.next().value); // 2
console.log(eArr.next().value); // 3
console.log(eArr.next().value); // 4
规范
Specification | Status | Comment |
---|---|---|
[ECMAScript 2015 (6th Edition, ECMA-262) | ||
%TypedArray%.prototype.keys()](https://www.ecma-international.org/ecma-262/6.0/#sec-%typedarray%.prototype.keys) | Standard | 初始定义。 |
[ECMAScript Latest Draft (ECMA-262) | ||
%TypedArray%.prototype.keys()](https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.keys) | Draft |
浏览器兼容性
We’re converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven’t yet converted the data it contains.
- Desktop
- Mobile
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | 37 (37) | 未实现 | 未实现 | 10 |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | 未实现 | (Yes) | 37.0 (37) | 未实现 | 未实现 | 10 |