CODEWITHSUNDEEP
javascriptarraysobject
aznmik
aznmik

Reputation: 45

javascript: unshift an object to an array of object

I have an object that i need to insert in the front(first index) of an array of object. 

const static_stat = {id: null, name: 'UNASSIGNED'};
api_data = [{id:.., name:..},{id:.., name:..},{id:.., name:..}];

I've tried using unshift, What I want is to achieve the result below, but it gives me the length of the array instead.

[{id:null, name: 'UNASSIGNED'},{id:.., name:..},{id:.., name:..},{id:.., name:..}]

Upvotes: 0

Views: 6398

Answers (2)

palaѕн
palaѕн

Reputation: 73936

Yes, you are right. The unshift() method adds one or more elements to the beginning of an array and returns the new length of the array. But after using unshift() your original array api_data has been already updated. Just use a console.log(api_data) on it to see the updated array with new static_stat object like:

const static_stat = {id: null, name: 'UNASSIGNED'};
let api_data = [{id: 1, name: 'Jhon'}];

console.log(api_data.unshift(static_stat));

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

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386746

Array#unshift mutates the array and returns the new length of the array.

For getting a new array, you could use Array#concat

return [static_stat].concat(api_data);

or take a new array with spreaded items.

return [static_stat, ...api_data];

Upvotes: 1

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