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()		 Standard 初始定义。
ECMAScript Latest Draft (ECMA-262)
%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. Find out how you can help!
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

另见