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]
TypeScript 1.0 was released at Microsoft's Build developer conference in 2014.[21]Visual Studio 2013 Update 2 provided built-in support for TypeScript.[22] 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.[23]
On 22 September 2016, TypeScript 2.0 was released, introducing several features, including the ability for programmers to optionally enforce null safety.[24]
TypeScript 3.0 was released on 30 July 2018,[25] bringing many language additions like tuples in rest parameters and spread expressions, rest parameters with tuple types, generic rest parameters and so on.[26]
TypeScript 4.0 was released on 20 August 2020.[27] While 4.0 did not introduce any breaking changes, it added language features such as Custom JSX Factories and Variadic Tuple Types.[27]
TypeScript 5.0 was released on 16 March 2023 and included support for decorators.[28]
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.[29]
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.[30]
Design
TypeScript originated from the shortcomings of JavaScript for developing large-scale applications both at Microsoft and among their external customers.[31] Challenges with dealing with complex JavaScript code led to demand for custom tooling to ease developing of components in the language.[32]
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.
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#.
As TypeScript is simply a superset of JavaScript, existing JavaScript can be adapted to TypeScript while TypeScript can seamlessly integrate 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.
Prior to version 7, the TypeScript compiler, named tsc, was written in TypeScript and compiled into regular JavaScript, allowing it to run in any JavaScript engine (e.g. a browser) or as a Node.js package. Beginning with TypeScript 7.0, released on 8 July 2026, the compiler and language service were rewritten in Go as a native binary, which Microsoft reported delivers full-build speedups typically between 8 and 12 times over the JavaScript-based TypeScript 6.0 compiler; for example, type-checking the Visual Studio Code codebase fell from 125.7 seconds to 10.6 seconds under default settings.[34] The native port began as an experimental preview distributed via the @typescript/native-preview npm package starting in 2025, which had accumulated more than 8.5 million weekly downloads before being merged into the standard typescript package for the 7.0 release.[34] TypeScript 7.0 shipped without a stable programmatic compiler API, which Microsoft said would be introduced in a subsequent 7.1 release; in the interim, tooling that depends on the compiler's API, such as certain features of Vue, Angular, and Svelte, required continued use of the JavaScript-based compiler.[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.
Native compilation
In 2026, Vercel released scriptc, an open-source compiler that compiles TypeScript and JavaScript programs into self-contained native executables without requiring Node.js, V8, or another JavaScript engine in the resulting binary.[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,[37] as well as their Visual Studio Add-in and extension, ReSharper 8.1.[38][39]
Atom has a TypeScript plugin with support for code completion, navigation, formatting, and fast compilation.[40]
Smarter type alias preservation, leading/middle rest elements in tuple types, stricter checks for the in operator, abstract construct signatures
Unsupported: 4.3
26May2021(2021-05-26)
Separate write types on properties, override and the --noImplicitOverride flag, template string type improvements
Unsupported: 4.4
26August2021(2021-08-26)
Control flow analysis of aliased conditions and discriminants, symbol and template string pattern index signatures
Unsupported: 4.5
17November2021(2021-11-17)
Type and promise improvements, supporting lib from node_modules, template string types as discriminants, and es2022 module
Unsupported: 4.6
28February2022(2022-02-28)
Type inference and checks improvements, support for ES2022 target, better ECMAScript handling
Unsupported: 4.7
24May2022(2022-05-24)
Support for ES modules, instantiation expressions, variance annotations for type parameters, better control-flow checks and type check improvements
Unsupported: 4.8
25August2022(2022-08-25)
Intersection and union types improvements, better type inference
Unsupported: 4.9
15November2022(2022-11-15)
satisfies operator, auto-accessors in classes (proposal), improvements in type narrowing and checks
Unsupported: 5.0
16March2023(2023-03-16)
ES decorators (proposal), type inference improvements, bundler module resolution mode, speed and size optimizations
Unsupported: 5.1
1June2023(2023-06-01)
Easier implicit returns for undefined and unrelated types for getters and setters
Unsupported: 5.2
24August2023(2023-08-24)
using declarations and explicit resource management, decorator metadata and named and anonymous tuple elements
Unsupported: 5.3
20November2023(2023-11-20)
Improved type narrowing, correctness checks and performance optimizations
Unsupported: 5.4
6 March 2024
Object.groupBy and Map.groupBy support
Unsupported: 5.5
20 June 2024
Inferred Type Predicates, Regular Expression Syntax Checking, and Type Imports in JSDoc
Unsupported: 5.6
9 September 2024
Advanced type inference, variadic tuple enhancements, partial module declarations
Unsupported: 5.7
22 November 2024
Refined variable initialization checks, improved module import handling (path rewriting), ES2024 support, and faster editor performance via Node.js compile cache
Unsupported: 5.8
28 February 2025
Granular type-checking for return expressions in conditional branches, the --erasableSyntaxOnly flag to ensure compatibility with Node.js's native TypeScript stripping
Unsupported: 5.9
31 July 2025
import defer for lazy/deferred module evaluation, a stable --module node20 option, expandable hover tooltips in editors, and an ~11% compiler speed improvement
Supported: 6.0
23 March 2026
Introduce 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.
↑"The Early History of F#"(PDF). Archived(PDF) from the original on 9 August 2024. 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].
↑Turner, Jonathan (2 April 2014). "Announcing TypeScript 1.0". TypeScript Language team blog. Microsoft. Archived from the original on 5 September 2015. Retrieved 20 October 2021.
↑de Icaza, Miguel (1 October 2012). "TypeScript: First Impressions". Archived from the original on 24 February 2019. 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.
↑"Microsoft TypeScript: Can the father of C# save us from the tyranny of JavaScript?". ZDNet. 1 October 2012. Archived from the original on 3 August 2014. 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.
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