jQuery - waiting for multiple AJAX requests to finish

Problem I am solving -

Wait for N or Multiple or Unknown number (Depends on some logic) of ajax request using JQuery to complete, i.e.

$.when(N ajax request).then(do something)

Lets take a look at easier version of the problem, what if we want to wait for only two calls


Well that was easy, so what... huh

What if you wana wait for n number of calls ? You cannot do $.when(call1, call2, ....., calln).then...

Lets take a look at a use case -

Lets say there is an array of ids and for each id in the array, we gota make a call and when all the data is loaded, we want to show a big red BLINK.

Here is how we gona do this -