How can i get all index of array,

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

Output should be like [0,1,2]

How can i get all index of array,

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

Output should be like [0,1,2]

• javascript
• arrays
• node.js

• 2 Please refer this AlexC stackoverflow./help/how-to-ask. Consider trying something before asking question. – manish kumar Commented May 10, 2019 at 9:54
• every array index start form zero and end at the number one less than the length of array. what you want to ask, ask properly – Faiz Khan Commented May 10, 2019 at 9:57

3 Answers 3

Simplest way would be to (see this post):

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

and the naive solution is by calling map((_, i) => i)) on your array:

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

You can use Object.keys also to check keys index of any object.

let a = [
        {
        'name' : "aloha",
        "age": "18"
        },
        {
        "name": "hello word"
        },
        {
        "name": "John Doe",
        "age" : "28"
    }]
    
console.log(Object.keys(a));

You can use forEach loop, like this example:

//The array you want to get all the indexes from
const array = [{'a':1}, {'b':2}, {'c':3}];
//All indexes array
const indexArray = [];

array.forEach((el, i) => {
    indexArray.push(i);
});