Filtering on Listing Screen

In Mosh’s Intro video on React native, he mentions about filtering the listing by tapping on the different categories on top of the screen.
If you look at the The Ultimate React Native Series: Fundamentals video - the first Introduction video at 1:13, demo’s the features to filter the listing screen.

But unfortunately, I did not see where Mosh actually explains how he coded this particular piece of functionality. I could do it myself but intrigued to see his approach. I dug deep into code repos regarding DoneWithIt on Github, but nothing.

Anyone seen it?