Tsc-ts: TypeScript written in TypeScript

An experimental TypeScript port of the TypeScript 7.0.2 compiler (TypeScript-Go, or tsgo), compiled to native code with scriptc.

Installation

Install the compiler from npm:

npm install -D tsc-ts
npx tsc-ts -p tsconfig.json

The tsc-ts package runs a native executable from a per-platform optional dependency (@tsc-ts/darwin-arm64, @tsc-ts/linux-x64-gnu, …). See packages/tsc-ts.

See CHANGELOG.md for release notes and GitHub Releases for package archives.

To build the packages for the current platform:

npm run pack:npm -w tsc-ts             # packages/tsc-ts/dist/npm/*.tgz
npm run pack:npm -w tsc-ts -- --check  # also install the tarballs and compile a project

-- --binary dist/tsc packs an existing native build, relative to packages/tsc-ts, instead of building one.

Packages

Package	Description
`packages/tsc-ts`	The compiler, written in TypeScript, with the `tsc-ts` command line and `--api` server.
`packages/tsgo`	Reference builds of tsgo (its command line and per-stage drivers) that the tests compare against.

Tasks run with Turborepo.

Documentation

apps/web contains the tsc-ts compiler guides.

npm run dev:web
npm run build:web

Requirements

Node.js 24+ and npm
Go 1.26
A scriptc host: macOS, Linux, or Windows, with clang available for linking

Build

npm ci
npm run fetch:upstream   # clone tsgo at the pinned commit
npm run build            # the Node build of tsc-ts (packages/tsc-ts/dist) and the documentation site
npm run build:oracle     # tsgo reference builds in packages/tsgo/dist

package.json pins scriptc 0.3.5, with its @scriptc/threads package. The build fails with any other version.

Compiler

packages/tsc-ts/src/compiler is the compiler, ported from tsgo 7.0.2 as idiomatic TypeScript. Each part is compared with tsgo on TypeScript's test corpus (about 12,500 files, 17,000 units after splitting multi-file cases):

Part	Compared with tsgo	Status
Scanner	tokens, values, errors, rescans, JSDoc	all files match
Parser and AST	tree, diagnostics, API source file encoding	all units match
Binder	symbols, tables, flow graph, name resolution	all units match
Module resolution	results, package IDs, `--traceResolution`	all requests match
`tsconfig.json` and programs	`--showConfig`, `--listFilesOnly`, `--explainFiles`	all cases match
Command line and options	output, errors, exit codes, `--locale`	all cases match
Diagnostics catalog	messages, 13 translations, output formats	all match
JavaScript emit	emitted files, 39 option sets	all compared units match
Declaration emit	`.d.ts` and `.d.ts.map` output, declaration errors	all units match
`--build`, `--incremental`	output, `.tsbuildinfo`, emitted files, `--watch`	all scenarios match
Type checker	diagnostics per file	all files match

The corpus scripts are in packages/tsc-ts/scripts (*-corpus.mjs).

API server

tsc-ts --api serves the same API as TypeScript 7.0.2's tsc --api, over stdin and stdout, so tools that drive tsc --api (such as scriptc) can run tsc-ts instead.

npm run build -w tsc-ts
node packages/tsc-ts/dist/tsc-ts/src/main.js --api --cwd path/to/project

Native builds read lib files from the executable's directory, or from TSC_TS_LIB_DIR:

npm run build:native -w tsc-ts       # packages/tsc-ts/dist/tsc
npm run build:native:dev -w tsc-ts   # unoptimized, faster to build
TSC_TS_LIB_DIR=upstream/typescript-go/internal/bundled/libs packages/tsc-ts/dist/tsc -p path/to/project

TSC_TS_BIN=packages/tsc-ts/dist/tsc runs the tsc-ts tests that take a native build against it.

The server is checked against tsc --api 7.0.2 response by response, and scriptc builds the same programs with either. It runs on the tsc-ts compiler, natively or under Node.

Language service methods are supported: getCompletionsAtPosition, getJsDocTags, getDocumentationComment, getReferencesToSymbolInFile, getReferencedSymbolsForNode and getSignatureUsages. Like tsc --api, completions that need auto imports (global identifiers, import statements, exhaustive switch cases) report completion list needs auto imports. The profiling methods (startCPUProfile, stopCPUProfile, saveHeapProfile) are not supported.

Testing

npm test                     # compare tsc-ts with tsgo
npm run bench -w tsc-ts      # time tsc-ts against tsgo and TypeScript's JavaScript compiler
npm run lint                 # oxlint
npm run format               # oxfmt

License

Apache-2.0. See THIRD_PARTY_NOTICES.md for TypeScript-Go and other third-party notices.