Question

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How to clone js object?

This is another way to create a javascript object (using object literal notation instead of function):

user = {
  name: "Foo",
  email: "[e-mail]"
}

Is there a way to clone this object or is it a singleton?

Answer 1

Try this:

var clone = (function(){ 
  return function (obj) { Clone.prototype=obj; return new Clone() };
  function Clone(){}
}());

Here’s what’s going on.

• Clone is a dummy constructor.
• We assign the object we want to clone to the Clone constructor’s prototype.
• We call Clone using ‘new’, so the constructed object has the original object as its constructor’s prototype aka (non-standard) __proto__.

The cloned object will share all the properties of the original object without any copies of anything being made. If properties of the cloned object are assigned new values, they won’t interfere with the original object. And no tampering of built-ins is required.

Keep in mind that an object property of the newly-created object will refer to the same object as the eponymous property of the cloned object. Assigning a new value to a property of the clone won’t interfere with the original, but assigning values to the clone’s object properties will.

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Try this in chrome or firebug console:

var user = {
  name: "Foo",
  email: "[e-mail]"
}

var clonedUser = clone(user);

console.dir(clonedUser);

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A detailed explanation of this cloning technique can be found here.