What is Typescript?

TypeScript (abbreviated as TS) is a free and open-source high-level programming language developed by Microsoft that adds static typing with optional type annotations to JavaScript. It is designed for the development of large applications and transpiles to JavaScript.

TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with Node.js, Deno or Bun). Multiple options are available for transpilation. The default TypeScript Compiler can be used,[7] or the Babel compiler can be invoked to convert TypeScript to JavaScript.

TypeScript supports definition files that can contain type information of existing JavaScript libraries, much like C++ header files can describe the structure of existing object files. This enables other programs to use the values defined in the files as if they were statically typed TypeScript entities. There are third-party header files for popular libraries such as jQuery, MongoDB, and D3.js. TypeScript headers for the Node.js library modules are also available, allowing development of Node.js programs within TypeScript.[8]

The TypeScript compiler is itself written in TypeScript and compiled to JavaScript. It is licensed under the Apache License 2.0. Anders Hejlsberg, lead architect of C# and creator of Delphi and Turbo Pascal, has worked on the development of TypeScript.

Compiler
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The TypeScript compiler, named tsc, is written in TypeScript. As a result, it can be compiled into regular JavaScript and can then be executed in any JavaScript engine (e.g. a browser). The compiler package comes bundled with a script host that can execute the compiler. It is also available as a Node.js package that uses Node.js as a host.

The compiler can "target" a particular edition of ECMAScript (such as ES5 for legacy browser compatibility), but by default compiles for the latest standards.
IDE and editor support
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Microsoft provides a plug-in for Visual Studio 2012 and WebMatrix, full integrated support in Visual Studio 2013, Visual Studio 2015, and basic text editor support for Emacs and Vim.[39]
Visual Studio Code supports TypeScript in addition to several other languages, and offers features like debugging and intelligent code completion.
alm.tools is an open source cloud IDE for TypeScript built using TypeScript, ReactJS and TypeStyle.
JetBrains supports TypeScript with code completion, refactoring and debugging in its IDEs built on IntelliJ platform, such as PhpStorm 6, WebStorm 6, and IntelliJ IDEA,[40] as well as their Visual Studio Add-in and extension, ReSharper 8.1.[41][42]
Atom has a TypeScript plugin with support for code completion, navigation, formatting, and fast compilation.[43]
The online Cloud9 IDE and Codenvy support TypeScript.
A plugin is available for the NetBeans IDE.
A plugin is available for the Eclipse IDE (version Kepler)
TypEcs is available for the Eclipse IDE.
The Cross Platform Cloud IDE Codeanywhere supports TypeScript.
Webclipse An Eclipse plugin designed to develop TypeScript and Angular 2.
Angular IDE A standalone IDE available via npm to develop TypeScript and Angular 2 applications, with integrated terminal support.
Tide – TypeScript Interactive Development Environment for Emacs.

Integration with build automation tools
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Main article: Build automation

Using plug-ins, TypeScript can be integrated with build automation tools, including Grunt (grunt-ts[44]), Apache Maven (TypeScript Maven Plugin[45]), Gulp (gulp-typescript[46]) and Gradle (TypeScript Gradle Plugin[