Lately I've been trying to lean back-end technologies. The big picture is that after learning the back-end I wanted to learn JavaScript and later get into a JS library or Framework. I'm pretty sure that I want to lean React (easy integration with Django) but the guy in this video is claiming that React is written in TypeScript and therefore I ask myself if learning TS is the better alternative to get into React. But as a matter of fact, I've never heard someone refer to React as TypeScript since it is described as a JS library.
What is the relation here? For me this is very important since I have to structure my learning plan.