The author seems to think that React users choose Flow and Angular users choose TypeScript.
However, TypeScript works really well with React and has for a long time. I have an example[0] boilerplate for isomorphic web app with React server-side rendering in TypeScript.
The code should be pretty easy to follow if you have some React experience. I chose to use the bare Node.js APIs so there is no favoritism in express, koa, hapi, etc.