Javascript Array to Object best way

Question

I have the following

 {
 bill: [ 
        { satisfy: 'true', comments: '' } 
       ],
 permission_title: [ 
        { satisfy: 'false', comments: '5' } 
       ],
 final_status: [ 
       { satisfy: 'true', comments: '' } 
       ] 
 }

And i need to send:

{
 bill: { satisfy: 'true', comments: '' },
 permission_title: { satisfy: 'false', comments: '5' },
 final_status: { satisfy: 'true', comments: '' } 
 }

What is the best and fast way to get it?

Possible duplicate of [Convert Array to Object](https://stackoverflow.com/questions/4215737/convert-array-to-object) — sumit, May 07 '18 at 22:16

score 2 · Answer 1 · answered May 07 '18 at 22:24

Extract the key/value pairs (entries) with Object.entries(). Iterate the entries with Array.map(). For each entry return an object with the key, and the value without the wrapping array. Merge back to an object by spreading into Object.assign():

const obj = {"bill":[{"satisfy":"true","comments":""}],"permission_title":[{"satisfy":"false","comments":"5"}],"final_status":[{"satisfy":"true","comments":""}]};

const result = Object.assign(
  ...Object.entries(obj).map(([k, v]) => ({
    [k]: v[0]
  }))
);

console.log(result);

score 2 · Accepted Answer · edited May 07 '18 at 22:48

2

Let's say your object is named obj. I would do it this way:

for(var p in obj) obj[p] = obj[p][0];

const obj={
 bill: [ 
        { satisfy: 'true', comments: '' } 
       ],
 permission_title: [ 
        { satisfy: 'false', comments: '5' } 
       ],
 final_status: [ 
       { satisfy: 'true', comments: '' } 
       ] 
 }
let obj_new=Object.assign(obj);
for(var p in obj_new) { obj_new[p] = obj_new[p][0] };
console.log(obj_new);

edited May 07 '18 at 22:48

sumit

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answered May 07 '18 at 22:31

Ivan Kuckir

2,327
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Easiest and cleanest way, I included the fiddle – sumit May 07 '18 at 22:36
This assumes it's ok to modify the original `obj`. – tony19 May 07 '18 at 22:45
we can add one additional line object.assign on the top of loop – sumit May 07 '18 at 22:50

score 0 · Answer 3 · answered May 07 '18 at 22:17

Assuming that every value has only one index, an alternative is using the function reduce along with the function Object.keys.

var obj = {  bill: [{    satisfy: 'true',    comments: ''  }],  permission_title: [{    satisfy: 'false',    comments: '5'  }],  final_status: [{    satisfy: 'true',    comments: ''  }]},
    result = Object.keys(obj).reduce((a, k) => (Object.assign(a, {[k]: obj[k][0]})), {});

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

score 0 · Answer 4 · answered May 07 '18 at 22:18

const src = {
 bill: [ 
        { satisfy: 'true', comments: '' } 
       ],
 permission_title: [ 
        { satisfy: 'false', comments: '5' } 
       ],
 final_status: [ 
       { satisfy: 'true', comments: '' } 
       ] 
 };
 
 const dest = Object.keys(src).reduce((prev, key) => {
    prev[key] = src[key][0];
    return prev;
 }, {});
 
 console.log(dest);

score 0 · Answer 5 · answered May 07 '18 at 22:20

I am not sure efficiency wise, but you can use the find function too!

const src = {
 bill: [ 
        { satisfy: 'true', comments: '' } 
       ],
 permission_title: [ 
        { satisfy: 'false', comments: '5' } 
       ],
 final_status: [ 
       { satisfy: 'true', comments: '' } 
       ] 
 };
 
 const dest = Object.keys(src).reduce((prev, key) => {
    if(Array.isArray(src[key])) {
        prev[key] = src[key].find(() => true);
    }
    
    return prev;
 }, {});
 
 console.log(dest);

Javascript Array to Object best way

5 Answers5