What is TypeScript written in?
The TypeScript compiler (tsc) is written in TypeScript itself, making it self-hosting. It compiles TypeScript to JavaScript, so the compiled tsc runs on any JavaScript engine. The TypeScript compiler and language services are fully self-hosted.
Quick Facts
- Short answer
- tsc is written in TypeScript
- Created by
- Anders Hejlsberg, Microsoft, 2012
- Output
- Transpiles to JavaScript
- Runtime
- None of its own, runs on JS engines
Details
TypeScript is self-hosting: the tsc compiler is written in TypeScript. This means TypeScript's compiler is compiled by itself, a previous version of tsc compiles the next version.
Since TypeScript compiles to JavaScript, the compiled tsc binary runs on Node.js or any JavaScript engine. This makes TypeScript's self-hosting unique: it's a compiled language whose compiler runs as interpreted JavaScript.
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