How to change indexes keys an array of object in JavaScript

Question

I have an array of object , [{name:'abc'},{name:'def'},{name:'ghi'}]. When I loop map() on this array I am getting array like [0:{name:'abc'},1:{name:'def'},2:{name:'ghi'}]. I want to change index number to string values like ['string1':{name:'abc'},'string2':{name:'def'},'string3:{name:'ghi'}]. Actually it will change ( 0, 1,2 ) indexes to string . I tried but didn't find any solution . Could someone please help me how to resolve this issue . ?

any simple example will be appreciated

Thanks

`['string1':{name:'abc'},'string2':{name:'def'},'string3:{name:'ghi'}]` is not valid — Andreas, Nov 12 '20 at 08:41
*"I tried but didn't find any solution"* Show us what you've tried — Cid, Nov 12 '20 at 08:44
_"I know but I have requirment"_ - It's irrelevant what the requirement says when it isn't possible because of invalid syntax o.O — Andreas, Nov 12 '20 at 08:45
and yes, you can't have associative arrays in JS, `[string1:{name:'abc'}]` is invalid, however, `{string1:{name:'abc'}}` is valid (object) — Cid, Nov 12 '20 at 08:46
As @Cid mentioned. Show us what is it that you tried that didn't work out — toesslab, Nov 12 '20 at 08:48
When you say you have a requirement it means it is most likely a homework question — , Nov 12 '20 at 09:08

Joshua · Accepted Answer · 2020-11-12T10:44:13.337

You need a data structure that allows indexing by a given key, you should try an object or a Map. Use an object if you're just trying to do something simple.

With that, you should have:

const names = {
  string1: {name:'abc'},
  string2: {name:'def'},
  string3: {name:'ghi'}
}

But I guess it can be simplified to this:

const names = {
  string1: 'abc',
  string2: 'def',
  string3: 'ghi'
}

But if you want to go the long way, which can give you something similar.

const names = [{name:'abc'},{name:'def'},{name:'ghi'}];
const entries = Object.fromEntries(names.entries());
const mappedNames = Object.keys(entries).map(key => [`string${key}`, entries[key]])

const newNames = Object.fromEntries(mappedNames)

which would give you:

{
  string0: {name:'abc'},
  string1: {name:'def'},
  string2: {name:'ghi'}
}

But you can't change the value of an array index.

score 0 · Answer 2 · answered Nov 12 '20 at 09:08

The syntax you described ['string1':{name:'abc'},'string2':{name:'def'},'string3:{name:'ghi'}] is invalid. Instead, combine for-of loops and object literals.

let obj = {};
let ind = 0;
for (const object of /*array name*/) {
  obj["string" + ind] = object;
  ind += 1;

How to change indexes keys an array of object in JavaScript

2 Answers2