Packages whose declarations name WebAssembly types (quickjs-wasi,
photon-node, and therefore pi) failed scriptc's type check with SC0001
"Cannot find namespace 'WebAssembly'", because scriptc's ES-only type
world never loads lib.dom, so `scriptc coverage` could not analyze them.
- scriptc.d.ts declares lib.dom's WebAssembly namespace and BufferSource
(admitting every ArrayBufferView, so Node's Buffer types fit).
- The type mapper gives every type declared in the namespace, and unions
over one, the checked-dynamic representation, so declarations that only
mention them compile.
- Every reached use of the API value refuses at its site with a named
SC2020 diagnostic: `WebAssembly.<member>` reads and calls,
`new WebAssembly.<Class>`, `instanceof WebAssembly.<Class>`, the bare
namespace, `globalThis.WebAssembly`, and the global object viewed
through a cast to a type with a WebAssembly member (pi codemode's
spelling). TypeScript sources fail the build; JavaScript sources get a
located runtime fence.
- `typeof WebAssembly` and `typeof WebAssembly.<member>` need no value and
fold to Node's answers ("object", "function"), including inside
`typeof x === "..."` tests, so feature probes in JavaScript glue behave
as in Node. Before, a JavaScript probe answered "string" (the identity
token) and silently took the non-wasm branch.
- The surface manifest projects the refusal (stdlib.webassembly), and the
compatibility ledger's `WebAssembly` global row moves from
not-implemented to refused; no other row changes.
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.