Concat arrays of objects

Question

I have few arrays with objects and I need to merge them in to one, but next code doesn't works, it return empty array:

let y = [{id:1, value: 'test1'}, {id:2, value: 'test2'}];
let z = [{id:3, value: 'test3'}, {id:4, value: 'test4'}];
let x = [{id:5, value: 'test5'}, {id:6, value: 'test6'}];
    
    
let arr = [];
    
arr.concat(...x,...y,...z);

console.log(arr);

`arr.concat` returns a *new array*…!? It does not modify `arr` in place. — deceze, Sep 14 '20 at 12:55
`concat` creates a new array. Change it to `arr.push(...x,...y,...z)` — adiga, Sep 14 '20 at 13:01

score 1 · Answer 1 · edited Sep 14 '20 at 12:57

1

Array.prototype.concat()

The concat() method is used to merge two or more arrays. This method does not change the existing arrays, but instead returns a new array

let y = [{id:1, value: 'test1'}, {id:2, value: 'test2'}];
let z = [{id:3, value: 'test3'}, {id:4, value: 'test4'}];
let x = [{id:5, value: 'test5'}, {id:6, value: 'test6'}];


let arr = [].concat(...x,...y,...z);

console.log(arr);

edited Sep 14 '20 at 12:57

Rahul Bhobe

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answered Sep 14 '20 at 12:56

Mamun

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Or just `[].concat(x,y,z)` – adiga Sep 14 '20 at 13:03

Concat arrays of objects

1 Answers1