Question

72

Javascript - How to clone an object?

rated 0 times [ 78] [ 6] / answers: 1 / hits: 36325 / 13 Years ago, tue, november 1, 2011, 12:00:00

I am confused. I create a copy from myObjOne, than i delete an entry from myObjOne and JS delete the entry in my copy(myObjTwo) too? But why?

  myObjOne = {};

  myObjOne['name'] = 'xxx';

  myObjOne['id'] = 'yyy';

  myObjOne['plz'] = 'zzz';  



  // clone

  myObjTwo = myObjOne;



  // remove something

  delete myObjOne['name'];



  console.dir(myObjTwo);

example
http://jsbin.com/itixes/edit#javascript,html

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

keric

Add To Favorites

Follow

Total Points: 572

Total Questions: 93

Total Answers: 97

Location: Cyprus

Member since Mon, Oct 24, 2022

2 Years ago

keric questions

1 Event.target.dataset returning undefined javascript

Thu, Dec 2, 21, 00:00, 3 Years ago

1 How to make a horizontal line without using < hr> tag?

Mon, Jul 19, 21, 00:00, 3 Years ago

1 Input with type=number that allows only numbers to be typed

Thu, Jul 15, 21, 00:00, 3 Years ago

1 Does declaring a React.memo inside another functional component provide the memoization performance as it is intended?

Sat, Jan 30, 21, 00:00, 3 Years ago

1 ReactJS useEffect() is running every time on page load

Thu, Nov 5, 20, 00:00, 4 Years ago

View All

answered 13 Years ago parkernotnamedt · Accepted Answer

Update: Removing Object.create as a method of cloning as indicated in comments.

  myObjTwo = myObjOne;

does not clone. It simply copies the reference.

If you want to clone, you can use JSON.parse and JSON.stringify

var x = {a:{b:{c:{'d':'e'}}}};

var y = JSON.parse(JSON.stringify(x));  //y is a clone of x

console.log(y.a.b.c.d); //prints e

console.log(y === x); //prints false

Warning: As Raynos mentioned in comments, this JSON based clone does not retain methods of the input object in the output object. This solution is good enough if your object does not contain any methods. Methods are properties of a object that are functions. If var obj = {add : function(a,b){return a+b;}} then add is a method of obj.

If you need a solution that supports copying of methods, then go through these SO answers (as pointed out by musefan, Matt and Ranhiru Cooray)

How do I correctly clone a JavaScript object?

What is the most efficient way to deep clone an object in JavaScript?

I would suggest How do I correctly clone a JavaScript object?