Javascript, repeating an object key N-times, being N its value

Question

I was wondering how to do this in the more cleaner and optimal way:

I have an Object with the following structure:

{
   \"125\": 2,
   \"439\": 3,
           


        

Answer 1

The problem with the other answers above is that the for..in language construct in javascript is going to involve all keys from the objects prototype chain. In this case, we should check and add only the correct keys.

var obj= {
   "125": 2,
   "439": 3,
   "560": 1,
   "999": 2
}

var arr=[];

for (var item in map) {
  //important check!
  if (map.hasOwnProperty(item)) {
    arr.push(item);
  }
}

Also see: http://www.yuiblog.com/blog/2006/09/26/for-in-intrigue/