Learn the fundamental pattern of building maintainable Redux applications: reducer composition, and how it can be used to update properties of an object.
This lesson seemed, to take a few extra leaps forward here, the pace previously had been easily understood and constant. The sudden appearance of the store and all the logs, utterly threw me, followed by the rather obfuscated explanation and example of the filters, which seemed almost abstract from the previous lesson. I had to double check I hadn't missed several steps, or even an entire lesson.
I prefer not to continually pause, rewind and play on lessons if its not necessary, but I have to admit, this lesson was a little slow on the uptake.