copy object with objects avoiding mutation of the initial object (avoid copy references)

Question

I have a question regarding copy of object by reference

I have a small snippet demonstrating the problem I want to not mutate the initial object I can do it by using immutable.js or some library, but I am wondering how it can be done with native js.

<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">

/////////// object Create 
let a = {
  "0": {

    "sortPluginSettings": {
      "columnSortType": "numeric",
      "sortingOrder": "noSort"
    }
  }
}
let b= Object.create(a)
console.log("a: ",a)
console.log("b: ",b)

b["0"].sortPluginSettings.sortingOrder="ascending"
console.log("NEWa: ",a) // OOPs mutated
console.log("NEWb: ",b[0])

/////////// object assign
let c = {
  "0": {

    "sortPluginSettings": {
      "columnSortType": "numeric",
      "sortingOrder": "noSort"
    }
  }
}
let e= Object.create(c)
console.log("c: ",c)
console.log("e: ",e)

e["0"].sortPluginSettings.sortingOrder="ascending"
console.log("NEWc: ",c) // OOPs mutated
console.log("NEWe: ",e[0])
</script>
    <title></title>
</head>
<body>

</body>
</html>

Behnam · Accepted Answer · 2017-07-12T05:08:49.457

0

use this way:

let a = {
  "0": {
    "sortPluginSettings": {
      "columnSortType": "numeric",
      "sortingOrder": "noSort"
    }
  }
}

var b= JSON.parse(JSON.stringify(a));

b[0].sortPluginSettings.columnSortType=null;

console.log(a);
console.log(b);

edited Jul 12 '17 at 05:08

answered Jul 11 '17 at 12:49

Behnam

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but note won't work if any functions in object – charlietfl Jul 11 '17 at 12:52
It works you are but it is not generic enough, what if you don't know exactly how many levels of deep objects you have you could do recursively but I am wondering of there is some other native method. Thank you nonetheless :) – partizanos Jul 11 '17 at 12:58
@partizanos updated code please try again – Behnam Jul 11 '17 at 13:00
It works but if the a : {} it keeps the original reference. For immutable types strins numbers boolean this will work you are right – partizanos Jul 11 '17 at 13:03
@partizanos vote :) – Behnam Jul 11 '17 at 13:06
sorry it doesn't work for nested object as in the example. only for strings , booleans and numbers – partizanos Jul 11 '17 at 13:32
@partizanos are you sure? please cheack again. updated code with your json – Behnam Jul 12 '17 at 05:09

copy object with objects avoiding mutation of the initial object (avoid copy references)

1 Answers1