This is a talk I gave at React Rally 2016 where I walked through a simplified implementation of React in order to explain how it worked. This simplified implementation is called Dilithium.
Be sure to check out the other talks too - all of the speakers did an amazing job.
I've included the annotated code that I used in my talk, in the dilithium directory. Keep in mind it probably differs slightly from what was shown in the slides (I took a few liberties to make it fit).