How can i copy an object in javascript correctly?

Question

I'm trying to copy an object in other using spread operator but wheni change one item from array in a copy object, the original is changed to. Any one knows how can i make the change only in object 2 ?

Follow a simple example:

let obj1 = { a:'hello', b:'hi', c: [1,2,3] }
let obj2 = { ...obj1 }
obj2.c[1] = 44

EDIT: This thread has the answer :) What is the most efficient way to deep clone an object in JavaScript?

Mosè Raguzzini · Accepted Answer · 2018-01-15T13:26:24.417

1

The most common and secure method is through Object.assign():

let clone = Object.assign({}, myObj);

It creates a shallow copy, if you want a deep copy you can use lodash deepClone(), for example or write yourself a recursive cloner.

edited Jan 15 '18 at 13:26

answered Jan 15 '18 at 13:14

Mosè Raguzzini

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i tryed this, but still change the both two. – Gustavo Hiroki Nakagawa Jan 15 '18 at 13:18
maybe you are doing it wrong, if you want a copy that's how you get it avoiding mutations so the error must be elsewhere. – Mosè Raguzzini Jan 15 '18 at 13:20
It changes the original when you change the array property in the cloned object.... https://jsfiddle.net/oyL4hxwx/ – Reinstate Monica Cellio Jan 15 '18 at 13:22
Updated the answer – Mosè Raguzzini Jan 15 '18 at 13:23
There's no lodash tag in the question ??? Sorry, but this is just wrong. – Reinstate Monica Cellio Jan 15 '18 at 13:23
ES6/ES7 does not have a deepClone, so you have to fallback on other tools or write a cloner by yourself – Mosè Raguzzini Jan 15 '18 at 13:24
I tested with the example above, when I change an element that is not an array this works, but when I change the array keeps changing the two. one solution I thought was: obj2.c = obj1.c.slice(); but i think thats not a god way to do this. – Gustavo Hiroki Nakagawa Jan 15 '18 at 13:24
Read previous comment – Mosè Raguzzini Jan 15 '18 at 14:49

How can i copy an object in javascript correctly?

1 Answers1