The amazing graphql tutorial by The Net Ninja done with Reacts functional components. https://www.youtube.com/playlist?list=PL4cUxeGkcC9iK6Qhn-QLcXCXPQUov1U7f
At some point I restructured the app to fit the functional pattern.
The original git repository can be found here: https://github.com/iamshaunjp/graphql-playlist