The revealing module pattern allows us to create private variables in a Javascript Module.
Here's a writeup on this pattern:
http://addyosmani.com/resources/essentialjsdesignpatterns/book/#revealingmodulepatternjavascript
Here's the code for this video:
http://codepen.io/anon/pen/ZGoKYN?editors=101
Here's video 1 in case you missed it:
https://www.youtube.com/watch?v=HkFlM73G-hk
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