How do I add a javascript object to an existing javascript object?

Question

var old = { 'a':3, 'b': 5 }
var new = { 'a': 999, 'c': 10 }

how do I append the "new" to the "old" and result in:

{ 'a': 999, 'b': 5, 'c': 10 }

Answer 1

If you're using a framework most have a function that will do it, e.g jQuery's extend. Otherwise if you're using JavaScript with no framework you'd have to do it yourself.

You could do it using a for...in loop.

for(var key in newObject)
{
    if(!newObject.hasOwnProperty(key)) {
         continue;
    }
    oldObject[key] = newObject[key];
}

As a side note don't call vars "new" its a keyword in more than a few languages. Np if its just for the example. I've renamed it in my example from new to newObject upon suggestions from the comments.

Psts right, needed to check in the for...in loop the var was actually new's