For the typed instance analogous to a handwritten document, see Manuscript.
TypeScript
ParadigmMulti-paradigm: functional, generic, imperative, object-oriented
FamilyECMAScript
DesignerMicrosoft,
Anders Hejlsberg,
Luke Hoban
DeveloperMicrosoft
Released1 October 2012 (age 13)[1]
Latest release date[2]
TypingDuck, gradual, strong, structural[3]
ScopeLexical
LicenseApache 2.0
File ext.ts, .tsx, .mts, .cts
Websitewww.typescriptlang.org
Influenced byC#, F#,[4] Java, JavaScript, ActionScript[5]
InfluencedAtScript, AssemblyScript, ArkTS

TypeScript (TS) is a high-level programming language that adds static typing with optional type annotations to JavaScript. It is designed for developing large applications. It transpiles to JavaScript.[6] It is developed by Microsoft as free and open-source software released under an Apache License 2.0.

TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with React.js, Node.js, Deno or Bun). Multiple options are available for transpiling. 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 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 developing TypeScript.[9][10][11][12]

History

TypeScript was released to the public in October 2012, with version 0.8, after two years of internal development at Microsoft.[13][14] Soon after the initial public release, Miguel de Icaza praised the language, but criticized the lack of mature integrated development environment (IDE) support apart from Microsoft Visual Studio, which was unavailable then on Linux and macOS.[15][16] As of April 2021 there is support in other IDEs and text editors, including Emacs, Vim, WebStorm, Atom[17] and Microsoft's own Visual Studio Code.[18] TypeScript 0.9, released in 2013, added support for generics.[19]

TypeScript 1.0 was released at Microsoft's Build developer conference in 2014.[20] Visual Studio 2013 Update 2 provided built-in support for TypeScript.[21] Further improvement were made in July 2014, when the development team announced a new TypeScript compiler, asserted to have a five-fold performance increase. Simultaneously, the source code, which was initially hosted on CodePlex, was moved to GitHub.[22]

On 22 September 2016, TypeScript 2.0 was released, introducing several features, including the ability for programmers to optionally enforce null safety.[23]

TypeScript 3.0 was released on 30 July 2018,[24] bringing many language additions like tuples in rest parameters and spread expressions, rest parameters with tuple types, generic rest parameters and so on.[25]

TypeScript 4.0 was released on 20 August 2020.[26] While 4.0 did not introduce any breaking changes, it added language features such as Custom JSX Factories and Variadic Tuple Types.[26]

TypeScript 5.0 was released on 16 March 2023 and included support for decorators.[27]

On March 11, 2025, Anders Hejlsberg announced on the TypeScript blog that the team is working on a Go port of the TypeScript compiler to be released as TypeScript version 7.0 later this year. It is expected to feature a 10x speedup.[28]

On December 2nd, 2025, Daniel Rosenwasser announced on the blog that TypeScript 6.0 will be the last release written in TypeScript itself, and TypeScript 7.0 will be the first Go-based release.[29]

Design

TypeScript originated from the shortcomings of JavaScript for developing large-scale applications both at Microsoft and among their external customers.[30] Challenges with dealing with complex JavaScript code led to demand for custom tooling to ease developing of components in the language.[31]

Developers sought a solution that would not break compatibility with the ECMAScript (ES) standard and its ecosystem, so a compiler was developed to transform a superset of JavaScript with type annotations and classes (TypeScript files) back into vanilla ECMAScript 5 code. TypeScript classes were based on the then-proposed ECMAScript 6 class specification to make writing prototypal inheritance less verbose and error-prone, and type annotations enabled IntelliSense and improved tooling.

Features

Main article: JavaScript syntax#TypeScript-specific features

TypeScript adds the following syntax extensions to JavaScript:

Syntactically, TypeScript is very similar to JScript .NET, another Microsoft implementation of the ECMA-262 language standard that added support for static typing and classical object-oriented language features such as classes, inheritance, interfaces, and namespaces. Other inspirations include Java and C#.

Compatibility with JavaScript

Further information: JavaScript

As TypeScript is simply a superset of JavaScript, existing JavaScript can be adapted to TypeScript and TypeScript program can seamlessly consume JavaScript. The compiler can target all ECMAScript versions 5 and above, transpiling modern features like classes and arrow functions to their older counterparts.

With TypeScript, it is possible to use existing JavaScript code, incorporate popular JavaScript libraries, and call TypeScript-generated code from other JavaScript.[33] Type declarations for these libraries are usually provided with the source code but can be declared or installed separately if needed.

Development tools

See also: List of TypeScript software and tools

Compiler

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 is currently being rewritten in Go for version 7.[34]

The compiler can target a given edition of ECMAScript (such as ECMAScript 5 for legacy browser compatibility), but by default compiles for the latest standards.

IDE and editor support

  • 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.[35]
  • 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,[36] as well as their Visual Studio Add-in and extension, ReSharper 8.1.[37][38]
  • Atom has a TypeScript plugin with support for code completion, navigation, formatting, and fast compilation.[39]
  • 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

Further information: Build automation

Using plug-ins, TypeScript can be integrated with build automation tools, including Grunt (grunt-ts[40]), Apache Maven (TypeScript Maven Plugin[41]), Gulp (gulp-typescript[42]) and Gradle (TypeScript Gradle Plugin[43]).

Linting tools

TSLint[44] scans TypeScript code for conformance to a set of standards and guidelines. ESLint, a standard JavaScript linter, also provided some support for TypeScript via community plugins. However, ESLint's inability to leverage TypeScript's language services precluded certain forms of semantic linting and program-wide analysis.[45] In early 2019, the TSLint team announced the linter's deprecation in favor of typescript-eslint, a joint effort of the TSLint, ESLint and TypeScript teams to consolidate linting under the ESLint umbrella for improved performance, community unity and developer accessibility.[46]

Release history

Version numberRelease dateSignificant changes
1 October 2012
18 June 2013
12 April 2014
6 October 2014performance improvements
12 November 2014protected modifier, tuple types
20 January 2015union types, let and const declarations, template strings, type guards, type aliases
20 July 2015ES6 modules, namespace keyword, for..of support, decorators
16 September 2015JSX support, intersection types, local type declarations, abstract classes and methods, user-defined type guard functions
30 November 2015async and await support,
22 February 2016constraints generics, control flow analysis errors, string literal types, allowJs
22 September 2016null- and undefined-aware types, control flow based type analysis, discriminated union types, never type, readonly keyword, type of this for functions
8 November 2016keyof and lookup types, mapped types, object spread and rest,
22 February 2017mix-in classes, object type,
27 April 2017async iteration, generic parameter defaults, strict option
27 June 2017dynamic import expressions, string enums, improved inference for generics, strict contravariance for callback parameters
31 August 2017optional catch clause variables
31 October 2017strict function types
31 January 2018constant-named properties, fixed-length tuples
27 March 2018conditional types, improved keyof with intersection types
14 May 2018support for symbols and numeric literals in keyof and mapped object types
30 July 2018project references, extracting and spreading parameter lists with tuples
27 September 2018mappable tuple and array types
30 November 2018stricter checking for bind, call, and apply
31 January 2019relaxed rules on methods of union types, incremental builds for composite projects
29 March 2019faster incremental builds, type inference from generic functions, readonly modifier for arrays, const assertions, type-checking global this
29 May 2019faster incremental builds, omit helper type, improved excess property checks in union types, smarter union type checking
28 August 2019Stricter generators, more accurate array spread, better Unicode support for identifiers
5 November 2019Optional chaining, nullish coalescing
20 February 2020Type-only imports and exports, ECMAScript private fields, top-level await
12 May 2020Improvements in inference, speed improvements
20 August 2020Variadic tuple types, labeled tuple elements
19 November 2020Template literal types, key remapping in mapped types, recursive conditional types
25 February 2021Smarter type alias preservation, leading/middle rest elements in tuple types, stricter checks for the in operator, abstract construct signatures
26 May 2021Separate write types on properties, override and the --noImplicitOverride flag, template string type improvements
26 August 2021Control flow analysis of aliased conditions and discriminants, symbol and template string pattern index signatures
17 November 2021Type and promise improvements, supporting lib from node_modules, template string types as discriminants, and es2022 module
28 February 2022Type inference and checks improvements, support for ES2022 target, better ECMAScript handling
24 May 2022Support for ES modules, instantiation expressions, variance annotations for type parameters, better control-flow checks and type check improvements
25 August 2022Intersection and union types improvements, better type inference
15 November 2022satisfies operator, auto-accessors in classes (proposal), improvements in type narrowing and checks
16 March 2023ES decorators (proposal), type inference improvements, bundler module resolution mode, speed and size optimizations
1 June 2023Easier implicit returns for undefined and unrelated types for getters and setters
24 August 2023using declarations and explicit resource management, decorator metadata and named and anonymous tuple elements
20 November 2023Improved type narrowing, correctness checks and performance optimizations
6 March 2024Object.groupBy and Map.groupBy support
20 June 2024Inferred Type Predicates, Regular Expression Syntax Checking, and Type Imports in JSDoc
9 September 2024Advanced type inference, variadic tuple enhancements, partial module declarations.
22 November 2024
28 February 2025
31 July 2025
23 March 2026Introduce some deprecations and breaking changes to align with the upcoming native codebase. Strict mode is now enabled by default. Last version with compiler and language service based on JavaScript before rewrite to Go language.
Rewrite in Go with faster performance.

See also

References

Citations

  1. ^ "TypeScript". CodePlex. Archived from the original on 3 April 2015. Retrieved 26 April 2015.
  2. ^ https://github.com/microsoft/TypeScript/releases
  3. ^ "Type Compatibility". TypeScript. Archived 12 March 2018 at the Wayback Machine. Retrieved 21 March 2018.
  4. ^ "The Early History of F#". Archived 9 August 2024 at the Wayback Machine. Retrieved 5 February 2024. TypeScript was directly influenced by F#: one of the originators of TypeScript was Luke Hoban, who began TypeScript (then called Strada) immediately after working on F# 2.0. Recently he noted the influence of F# on early parts of the TypeScript design [Hoban 2017].
  5. ^ Nelson, Gary (28 April 2020). "How ActionScript foreshadowed TypeScript". Medium. Archived 9 August 2024 at the Wayback Machine. Retrieved 9 July 2022.
  6. ^ Bright, Peter (3 October 2012). "Microsoft TypeScript: the JavaScript we need, or a solution looking for a problem?". Ars Technica. Condé Nast. Archived 9 October 2018 at the Wayback Machine. Retrieved 26 April 2015.
  7. ^ "TypeScript Programming with Visual Studio Code". code.visualstudio.com. Archived 22 September 2022 at the Wayback Machine. Retrieved 12 February 2019.
  8. ^ "borisyankov/DefinitelyTyped". GitHub. Archived 1 November 2015 at the Wayback Machine. Retrieved 26 April 2015.
  9. ^ Foley, Mary Jo (1 October 2012). "Microsoft takes the wraps off TypeScript, a superset of JavaScript". ZDNet. CBS Interactive. Archived 13 November 2014 at the Wayback Machine. Retrieved 26 April 2015.
  10. ^ Somasegar, S. (1 October 2012). "TypeScript: JavaScript Development at Application Scale". Somasegar's blog. Microsoft. Archived 26 September 2017 at the Wayback Machine. Retrieved 26 April 2015.
  11. ^ Baxter-Reynolds, Matt (1 October 2012). "Microsoft TypeScript: Can the father of C# save us from the tyranny of JavaScript?". ZDNet. Archived 3 August 2014 at the Wayback Machine. Retrieved 26 April 2015.
  12. ^ Jackson, Joab (1 October 2012). "Microsoft Augments Javascript for Large-scale Development". CIO. IDG Enterprise. Archived from the original on 17 December 2013. Retrieved 26 April 2015.
  13. ^ "Microsoft augments JavaScript for large-scale development". InfoWorld. IDG. 1 October 2012. Archived 31 May 2013 at the Wayback Machine. Retrieved 26 April 2015.
  14. ^ Turner, Jonathan (2 April 2014). "Announcing TypeScript 1.0". TypeScript Language team blog. Microsoft. Archived 5 September 2015 at the Wayback Machine. Retrieved 20 October 2021.
  15. ^ de Icaza, Miguel (1 October 2012). "TypeScript: First Impressions". Archived 24 February 2019 at the Wayback Machine. Retrieved 12 October 2012. But TypeScript only delivers half of the value in using a strongly typed language to Unix developers: strong typing. Intellisense, code completion and refactoring are tools that are only available to Visual Studio Professional users on Windows. There is no Eclipse, MonoDevelop or Emacs support for any of the language features.
  16. ^ "Microsoft TypeScript: Can the father of C# save us from the tyranny of JavaScript?". ZDNet. 1 October 2012. Archived 3 August 2014 at the Wayback Machine. Retrieved 12 October 2012. And I think this is a pretty big misstep. If you're building web apps that run on anything other than Windows, you're likely using a Mac and most likely not using Visual Studio. You need the Visual Studio plug-in to get the IntelliSense. All you get without Visual Studio is the strong-typing. You don't get the productivity benefits you get from IntelliSense.
  17. ^ "TypeStrong: The only TypeScript package you will ever need". GitHub. Archived 19 December 2018 at the Wayback Machine. Retrieved 21 July 2016.
  18. ^ Hillar, Gastón (14 May 2013). "Working with TypeScript in Visual Studio 2012". Dr. Dobb's Journal. Archived 29 September 2018 at the Wayback Machine. Retrieved 26 April 2015.
  19. ^ "TypeScript 0.9 arrives with new compiler, support for generics". The Register. 18 June 2013. Archived 11 March 2018 at the Wayback Machine. Retrieved 26 April 2015.
  20. ^ Hejlsberg, Anders (2 April 2014). "TypeScript". Channel 9. Microsoft. Archived 25 May 2015 at the Wayback Machine. Retrieved 26 April 2015.
  21. ^ Jackson, Joab (25 February 2014). "Microsoft TypeScript graduates to Visual Studio". PC World. IDG. Archived 11 March 2016 at the Wayback Machine. Retrieved 26 April 2015.
  22. ^ Turner, Jonathan (21 July 2014). "New Compiler and Moving to GitHub". TypeScript Language team blog. Microsoft. Archived from the original on 22 July 2014. Retrieved 26 April 2015.
  23. ^ Bright, Peter (22 September 2016). "TypeScript, Microsoft's JavaScript for big applications, reaches version 2.0". Ars Technica. Condé Nast. Archived 21 December 2018 at the Wayback Machine. Retrieved 22 September 2016.
  24. ^ "Announcing TypeScript 3.0". 30 July 2018. Archived 30 May 2020 at the Wayback Machine. Retrieved 16 March 2020.
  25. ^ "TypeScript 3.0". 30 July 2018. Archived 6 June 2020 at the Wayback Machine. Retrieved 16 March 2020.
  26. ^ "Announcing TypeScript 4.0". TypeScript. 20 August 2020. Archived 9 August 2024 at the Wayback Machine. Retrieved 30 October 2020.
  27. ^ "Documentation – TypeScript 5.0". www.typescriptlang.org. Archived 9 August 2024 at the Wayback Machine. Retrieved 18 May 2023.
  28. ^ Hejlsberg, Anders (2025-03-11). "A 10x Faster TypeScript". TypeScript. Retrieved 2025-03-11.
  29. ^ Rosenwasser, Daniel (2025-12-02). "Progress on TypeScript 7". TypeScript. Retrieved 2026-03-21.
  30. ^ Hejlsberg, Anders (5 October 2012). "What is TypeScript and why with Anders Hejlsberg". www.hanselminutes.com. Archived 27 December 2018 at the Wayback Machine. Retrieved 15 January 2014.
  31. ^ Somasegar, S. (1 October 2012). "TypeScript: JavaScript Development at Application Scale". msdn.com. Archived 22 April 2015 at the Wayback Machine. Retrieved 27 November 2013.
  32. ^ "Documentation – TypeScript 5.2". www.typescriptlang.org. Archived 9 August 2024 at the Wayback Machine. Retrieved 9 November 2023.
  33. ^ "Welcome to TypeScript". typescriptlang.org. Microsoft. Archived 10 March 2018 at the Wayback Machine. Retrieved 26 April 2015.
  34. ^ Lawson, Darryl K. Taft, Loraine (2025-03-12). "Go Power: Microsoft's Bold Bet on Faster TypeScript Tools". The New Stack. Retrieved 2026-01-06.
  35. ^ Bloch, Olivier (1 October 2012). "Sublime Text, Vi, Emacs: TypeScript enabled!". Microsoft. Archived 29 October 2012 at the Wayback Machine. Retrieved 28 October 2012.
  36. ^ "TypeScript support in WebStorm 6". JetBrains. 27 February 2013. Archived 2 June 2016 at the Wayback Machine. Retrieved 20 April 2013.
  37. ^ "TypeScript support in ReSharper 8.1". JetBrains. 28 October 2013. Archived 2 February 2014 at the Wayback Machine. Retrieved 21 January 2014.
  38. ^ "ReSharper: The Visual Studio Extension for .NET Developers by JetBrains". JetBrains
  39. ^ "atom-typescript". Atom. Archived 4 October 2016 at the Wayback Machine. Retrieved 9 January 2020.
  40. ^ "TypeStrong/grunt-ts". GitHub. Archived 16 April 2020 at the Wayback Machine. Retrieved 26 April 2015.
  41. ^ "ppedregal/typescript-maven-plugin". GitHub. Archived 11 June 2018 at the Wayback Machine. Retrieved 26 April 2015.
  42. ^ "ivogabe/gulp-typescript". GitHub. Archived 11 June 2018 at the Wayback Machine. Retrieved 14 July 2017.
  43. ^ "sothmann/typescript-gradle-plugin". GitHub. Archived 11 June 2018 at the Wayback Machine. Retrieved 26 April 2015.
  44. ^ "TSLint". palantir.github.io. Archived 21 December 2022 at the Wayback Machine. Retrieved 11 February 2019.
  45. ^ Palantir (19 February 2019). "TSLint in 2019". Medium. Retrieved 24 April 2019.
  46. ^ "TSLint Deprecated to Focus Support on typescript-eslint". InfoQ. Archived 9 August 2024 at the Wayback Machine. Retrieved 24 April 2019.

Sources