Compile cost (Hono fixture: 53 s -> 99 s with the overlay before): - The overlay is planned once per program text: a reload that only drops refused annotations renders the cached plan (overlay.ts plan/render split) and reuses the cached structural rewrites, instead of analyzing, reporting and planning again. - The overlay's analyses run without per-call-site clones, which only the constant-graph report uses so far (SCRIPTC_SHAPE_SITE_CLONES opts in). - A failing round also drops what the deferred refusals blame, saving a reload; deferred refusals no longer blame every annotation of their enclosing function (most of them exist without the overlay). - A parameter whose `typeof` tests the proven values never pass stays untyped: the typed parameter would narrow to never in that branch, which the lowering refuses (zod 4's Doc.write). - Deferred refusals in methods blame the arguments of the method's call sites (implicit instantiations), like those in functions. Package JSDoc: the overlay neutralized the package's JSDoc in every overlaid file, so declarations it does not type lost their documented types and the lowering instantiated them per call site instead. In commander, this changed which refusal `--help` reaches: the run passed the refusal the default build stops at and failed later, in Command.helpInformation, at a checked conversion of the package's own documented contract (a help width that is undefined off a TTY). Nothing the analysis proved was contradicted (SCRIPTC_SHAPE_CHECK_LOG logs no inferred-fact failure). Only the leading JSDoc of the declarations the overlay annotates is neutralized now; commander's overlay build fails exactly where its default build does, and the OVERLAY_KNOWN entries go. The overlay npm suite (134 cases), the shape tests, lint and format pass. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
scriptc
scriptc compiles TypeScript and JavaScript to native executables and WebAssembly. It uses the types checked by the TypeScript compiler to generate machine code, and the output runs without Node.js installed. npm packages your program imports compile along with it. Code scriptc can't compile is reported at build time with a diagnostic and, where available, a rewrite hint.
scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. Run scriptc coverage on an existing program to see how much of it compiles, and see the limitations and Node.js compatibility reference for details.
Installation
Install with Node.js 24 or later and npm:
$ npm install -g scriptc
The installed compiler runs natively on macOS, Linux, and Windows. Node.js is needed only to install it and to run WASI modules with scriptc run. Standalone compiler archives are also available from GitHub Releases.
Building executables requires a linker and the platform SDK or sysroot. See the quickstart for prerequisites and platform support for host requirements, cross-compilation, and WebAssembly.
Build a program
Create hello.ts:
const who = process.argv.length > 2 ? process.argv[2] : "world";
console.log(`hello, ${who}`);
scriptc run compiles the file and runs the result:
$ scriptc run hello.ts
hello, world
scriptc build writes an executable:
$ scriptc build hello.ts -o hello >/dev/null
$ ./hello scriptc
hello, scriptc
These examples use POSIX shell syntax. On Windows, build hello.exe and run it with .\hello.exe.
Use scriptc coverage hello.ts to check what compiles before you build. See coverage reports for details.
Use Node APIs
Supported Node APIs compile to the native runtime. For example, server.ts:
import { createServer } from "node:http";
const server = createServer((req, res) => {
res.setHeader("content-type", "application/json");
res.end(JSON.stringify({ path: req.url }));
});
server.listen(8080, () => {
console.log("listening on http://localhost:8080");
});
$ scriptc build server.ts -o server >/dev/null
$ ./server
listening on http://localhost:8080
Use npm packages
npm packages compile into the executable with your code, so it doesn't read node_modules at runtime.
Create cli.ts:
import pc from "picocolors";
console.log(pc.green("hello from scriptc"));
$ npm install picocolors
$ scriptc build cli.ts -o cli >/dev/null
$ ./cli
hello from scriptc
Package support is partial. See npm dependencies for which packages compile and how to check them.
Documentation
- Introduction: what scriptc is and what you can build.
- Quickstart: installation and your first executable.
- Coverage reports: check whether an existing program compiles.
- Platform support: cross-compilation and WebAssembly.
- CLI reference: commands, options, and output formats.
- Native program objects: use compiler output in external builds.
- Native FFI: call C ABI functions from compiled programs.
- WebAssembly modules: build and embed WASI modules.
- Examples: programs and integration examples in this repository.
Contributing
See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.