如何获取数组的所有索引

Question

我怎样才能获得数组的所有索引，

[  
   {  
      "name":"aloha",
      "age":"18"
   },
   {  
      "name":"hello word"
   },
   {  
      "name":"John Doe",
      "age":"28"
   }
]

输出应该像[0,1,2]

Answer 1

最简单的方法是（参见这篇文章）：

let a = [{1: 'x'}, {1: 'y'}, {1: 'z'}]
let b = Array.from(a.keys())
console.log(b)

最简单的解决方案是调用map((_, i) => i))您的数组：

let a = [{1: 'x'}, {1: 'y'}, {1: 'z'}]
let b = a.map((_, i) => i)
console.log(b)