- 把一个
对象
所有属性复制到数组
中
let o = {x:1,y:2,z:3}
let a = []
let i = 0
for(a[i++] in o); //注意 ; 不能省略 (空循环体)
console.log(a) //['x', 'y', 'z']
- 再枚举出数组
索引
let o = {x:1,y:2,z:3}
let a = []
let i = 0
for(a[i++] in o);
for(let i in a)
console.log(i) //0 1 2