You need to understand JavaScript and the ecosystem. Even if you're going to be writing TypeScript, other people will probably be using regular JavaScript. But

You need to understand JavaScript and the ecosystem. Even if you're going to be writing TypeScript, other people will probably be using regular JavaScript. But TypeScript is a superset of JavaScript, so it shouldn't be very difficult to pick it up. You need to learn to crawl before you can walk, as they say. If you want to develop an in-depth understanding of the language, I suggest reading through the ExploringJS [0] series. It covers pretty much every single edge case and detail. You don't have to read each book cover-to-cover, you can just skim parts you're familiar with. To give you an idea of how awesome it is... Exploring ES6 is my go-to reference for anything related to ES6. When I first discovered the book I'd already been writing ES6 code for a while, and I thought I knew everything there was to know about it. But upon reading it, I was blown away by how many things I hadn't been aware of. [0] http://exploringjs.com http://exploringjs.com