referencing variable in javascript

Question

var items = new Array("one", "two", "three");
var itemsRef = items;
items.push("four");
console.debug(itemRef);
console.debug(items);

I really dont get the idea how above items and itemsRef are same even items added "four" when after itemsRef referenced items. Isn't it reasonable that itemsRef should have only ("one" "two" "three")?

If itemsRef keep pointing items forever, why do we use such an useless argument like items = itemsRef? I am still not getting the idea. Can anybody tell me how this is works and why JavaScript let variables pointing each other forever?

You're correct about what the code does, but as for why this particular code is written that way, it's pointless as far as I can tell. — Wyzard
– Wyzard, Commented May 4, 2012 at 1:07
I agree with Wyzard. You wouldn't typically see that. Is your goal to make a copy of an array? — Marc
– Marc, Commented May 4, 2012 at 1:08
Javascript arrays are assigned by reference: hunlock.com/blogs/Mastering_Javascript_Arrays — Chase
– Chase, Commented May 4, 2012 at 1:10

Marc · Accepted Answer · 2012-05-04 01:09:43Z

4

Javascript makes assignments of Objects and Arrays by reference instead of by value/copy. That's why you're seeing that behavior. There's plenty of web documentation about that.

But if your goal is to copy an array, do this:

var newArray = oldArray.slice(0);

answered May 4, 2012 at 1:09

Marc

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MK_Dev · Accepted Answer · 2012-05-04 01:10:17Z

1

In this case itemsRef is not pointing at items, but rather at the object (array) items reference is pointed at. In other word, items and itemsRef point to the same object and not each other.

answered May 4, 2012 at 1:10

MK_Dev

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