Does Javascript have associative arrays?

Question

Does Javascript have associative arrays? Please explain.

Answer 1

The closest we have is an object; the easiest way you can define this is using object literal syntax.

var assocArray = {
   key: 1,
   key2: 2
};

You should be wary of a few things however:

1. It does not have a .length property.

2. You should use for in to iterative over it, rather than for(;;;);, but should combine it with hasOwnProperty():

   for (var x in assocArray) {
       if (assocArray.hasOwnProperty(x)) {
           // x = the key, assocArray[x] = the value 
       }
   }
   

3. There is no concept of ordering/ sorting the members. Whilst all implementations I know of iterate the members in the order they were added, this is not standardised.