Polls.update({_id: id}, {$set : {already_voted[length]: ip});

Now this obviously doesn't work. I can't simply put a variable length in there.

Basically I have already_voted which is an array and I want to add a new ip to this array. The way I handle this currently is by getting the old length and using the old length as the new index to add the element.

I am wondering how I should go about doing this as my current setup does not work.

To clarify : I don't have the whole array, I just want to add a new element into the array in the Poll document.