Eval on clone object changes values of parent object

Asked May 03 '20 at 07:02

Active May 03 '20 at 07:18

Viewed 15 times

This is a part of a large function, but to put it simply:

var round1 = {gg: "wp"};
var round2 = round1;
eval('round2.gg="bp"')

This gives:

   round2 == {gg: 'bp'}

But also changes:

  round1 == {gg: 'bp'}

How to get around this ?

Edit: why I need eval ?

As a part of my function, i have the paths of the bigobject recorded as strings in an array, such that i can use eval to change the value of a specific property and copy it in a cloned object.

Example:

var bigobject = {
  a: { x: "1", y: "2" },
  //b: similar
}
var pathobject [".a.x",".a.y",".b.x",".b.y"]


// This eval is run in loop, so i = index of loop. but lets say i=0
var temp_object = bigobject;
var i=0;
eval('temp_object' + pathobject[i] + '=' + '5');

edited May 03 '20 at 07:18

asked May 03 '20 at 07:02

Subrata Rabidas

Please provide enough code to show why an eval is at all needed here. You need to clone the object and then just do `round2["gg"]="bp"` – mplungjan May 03 '20 at 07:07
hi, i have edited the question, please look. – Subrata Rabidas May 03 '20 at 07:18
`const [,n,m]=pathobject[i].split("."); temp_object[n][m]=5` - no need for eval – mplungjan May 03 '20 at 08:14
I can't do temp_object[n][m] directly because [n][m] is generated from loop, thats why i eval [n][m] which is basically a string. – Subrata Rabidas May 03 '20 at 08:21
I generate n and m from ".a.x" from the loop, so n="a" and m="x" - – mplungjan May 03 '20 at 08:30

Eval on clone object changes values of parent object

0 Answers0