Free TypeScript Courses for Intermediates

Scrimba's interactive TypeScript course teaches you to add types to JavaScript. Covers type annotations, interfaces, generics, enums, tuples, and TypeScript with React.

The Odin Project's TypeScript section covers type systems, interfaces, generics, enums, and integrating TypeScript into existing JavaScript projects.

The TypeScript module of Full Stack Open. Covers static typing, generics, type-safe React, and adding TypeScript to existing Node.js and Express projects.