
TypeScript: a language for developing large JavaScript applications

Microsoft introduced the TypeScript programming language , which is a superset of JavaScript, supports static typing, modules, definition of classes and interfaces. TypeScript translates to pure JS, runs in any browser, in Node.js, etc.
TypeScript translator was released under the Apache 2.0 license, with source code on CodePlex . Microsoft offers plugins for Emacs, Sublime Text, and Vim .
A superset of TypeScript is made to implement the functions needed to develop and support large applications. Static code analysis, symbolic navigation, autocompletion of functions, code refactoring and much more are supported. At the same time, full compatibility with JavaScript is maintained.

Playground - comparison of TypeScript and JavaScript on any code. TypeScript was released exactly one year later (almost a day per day) from the time Google introduced the Dart programming language . Unlike Google, Microsoft immediately released a whole set of tools with TypeScript and declared absolute compatibility with JavaScript. It looks like TypeScript can be used in serious applications right now, while the release of Dart seems not quite prepared.
