When a JavaScript codebase grows, it can become hard to read and maintain. TypeScript is an extension of JavaScript, adding static types. The TypeScript compiler reads in TypeScript code that includes type information and produces clean, readable JavaScript with the type information transformed and removed. The compiled code can then run in our favorite browsers and Node.js.

TypeScript offers several benefits over JavaScript:

• Coding errors can be caught in the development process earlier
• Static types allow tools to be built that improve the developer experience and productivity
• JavaScript features that aren't implemented in all the browsers yet can actually be used in an app that targets those browsers

We'll go through these points in detail in the following sections.