React
Academy
TypeScript is a better JavaScript. As a language, it is a superset of JavaScript that adds types and other features to the language. It also allows transpiling modern JavaScript into older JavaScript (so it can run on older devices).
Here are a few popular projects that are using Typescript: Office Online, Visual Studio Code, AirBnb, Angular (Google), Lyft, Vue, Aurelia, Ubisoft, Slack and much more.