I found a lot of related questions with answers talking about for...in loops and using hasOwnProperty but nothing I do works properly. All I want to do is check whether or not a key exists in an array and if not, add it.

I start with an empty array then add keys as the page is scrubbed with jQuery.

Initially, I hoped that something simple like the following would work: (using generic names)

if (!array[key])

   array[key] = value;

No go. Followed it up with:

for (var in array) {

   if (!array.hasOwnProperty(var))

      array[key] = value;

}

Also tried:

if (array.hasOwnProperty(key) == false)

   array[key] = value;

None of this has worked. Either nothing is pushed to the array or what I try is no better than simply declaring array[key] = value Why is something so simple so difficult to do. Any ideas to make this work?