The TypeScript language and compiler has been a huge success story since its release in late 2012. It quickly carved out a solid footprint in the JavaScript development community, and continues to go from strength to strength. Many large-scale JavaScript projects, including projects by Adobe, Mozilla, and Asana, have made the decision to switch their code base from JavaScript to TypeScript. In 2014, the Microsoft and Google teams announced that Angular 2.0 would be developed using TypeScript, thereby merging Google's AtScript language and Microsoft’s TypeScript languages into one.

This large-scale industry adoption of TypeScript shows the value of the language, the flexibility of the compiler, and the productivity gains that can be realized with its rich development toolset. On top of this industry support, the ECMAScript 6 and ECMAScript 7 standards are getting closer and closer to publication, and TypeScript provides a way to use features of these standards in our applications today.

Writing TypeScript applications has been made even more appealing with the large collection of declaration files that have been built by the TypeScript community. These declaration files seamlessly integrate a large range of existing JavaScript frameworks into the TypeScript development environment, bringing with it increased productivity, early error detection, and advanced IntelliSense features.

The JavaScript language is not confined to web browsers, however. We can now write server-side JavaScript, drive mobile phone applications using JavaScript, and even control micro devices designed for the Internet of Things with JavaScript. All of these JavaScript targets are therefore accessible to a developer writing TypeScript, because TypeScript generates JavaScript.