How to add value to an object which is inside an array in JavaScript?

Question

I have an array with multiple object into it,

const tokens = 
      [ { to: "abc", sound: "default" } 
      , { to: "def", sound: "ring"    } 
      , { to: "ghi", sound: "vibrate" } 
      ]

Further i want to add 2 different value say title and body to each object something like this :-

Note:- I have more than 300-400 objects in array "tokens" so please try to reply with an efficient code

const tokens = 
      [ { to: "abc", sound: "default", title: "test", body: "test2" } 
      , { to: "def", sound: "Ring",    title: "test", body: "test2" } 
      , { to: "ghi", sound: "vibrate", title: "test", body: "test2" }
      ]

Please Let me know how this can be done in JavaScript ?

both will work for me, if possible let me know for both the ways.(there are 300-400 objects in array so try with an efficient way) — Adarsh Jaiswal
– Adarsh Jaiswal, Commented Feb 22, 2020 at 21:24

Nina Scholz · Accepted Answer · 2020-02-22 21:26:19Z

3

You could take a non mutate approach and get a new array with new objects without altering the given data.

var tokens = [{ to: "abc", sound: "default" }, { to: "def", sound: "Ring" }, { to: "ghi", sound: "vibrate" }],
    result = tokens.map(o => ({ ...o, title: "test", body: "test2" }));

console.log(result);

answered Feb 22, 2020 at 21:26

Nina Scholz

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3 Comments

TheMaster Over a year ago

Isn't creating new objects slower than writing to the same object?

Nina Scholz Over a year ago

@TheMaster, yes it is. does it matter?

TheMaster Over a year ago

I mean op said, so please try to reply with an efficient code. So, I was wondering if it is efficient. You specifically mentioned non mutate approach. So, just wondering if I'm missing something.

Mister Jojo · Accepted Answer · 2020-02-22 21:43:06Z

1

you can also use this way

const tokens = 
      [ { to: "abc", sound: "default" } 
      , { to: "def", sound: "ring"    } 
      , { to: "ghi", sound: "vibrate" } 
      ] 


tokens.forEach(e=>{ e.title= "test"; e.body= "test2" })

console.log( tokens )

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

an other way:

const tokens = 
      [ { to: "abc", sound: "default" } 
      , { to: "def", sound: "ring"    } 
      , { to: "ghi", sound: "vibrate" } 
      ] 
      newElements = {title:'test', body:'test2'}
      ;
tokens.forEach(e=>Object.assign(e, newElements))

console.log( tokens )

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

edited Feb 22, 2020 at 21:43

answered Feb 22, 2020 at 21:38

Mister Jojo

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