TypeScript: Design-Time tool for Application-scale JavaScript development

TypeScript starts from the syntax and semantics that millions of JavaScript developers know today.

With TypeScript, you can use existing JavaScript code, incorporate popular JavaScript libraries, and be called from other JavaScript code.

TypeScript compiles to clean, simple JavaScript code which runs on any browser, in Node.js, or in any other ES3-compatible environment.

TypeScript offers classes, modules, and interfaces to help you build robust components.

These features are available at development time for high-confidence application development, but are compiled into simple JavaScript.

TypeScript types let you define interfaces between software components and to gain insight into the behavior of existing JavaScript libraries.