Using jQuery and CoffeeScript in WordPress

If you're properly enqueuing scripts and styles into your WordPress plugins and themes, you may have noticed this doesn't work:

$(document).ready(function () {
  alert($(".container").length);
});

jQuery

The solution, using jQuery, is this:

jQuery(document).ready(function ($) {
  alert($(".container").length);
});

You have to pass the $ to the ready function before you can effectively use it.

CoffeeScript

The CoffeeScript equivalent to this is:

jQuery(document).ready ($) ->
  alert $('.container').length;

Short, simple, but a frustration saver.