A build now translates every WebAssembly module whose bytes it can see (W2's discovery) into LLVM IR with a TypeScript translator (packages/compiler/src/wasm/module.ts, translate.ts) and appends it to the program module, so the existing LLVM helper optimizes, partitions and caches it with the program. The program also emits scr_wasm_registry, a portable table of module descriptors (scr_wasm_abi.h). At run time, WebAssembly.compile, instantiate, validate, new Module and new Instance find the translated module by the SHA-256 of its bytes; bytes the build did not see reject with a CompileError. There is no interpreter and no JIT. The runtime (scr_wasm.c, link-gated by the new `wasm` feature, handle tags inside W0's headroom) implements the JavaScript API once, over descriptors, with Node's semantics and messages: exports (functions, memories, tables, globals), imports (functions, immutable globals, and memories, tables and globals other instances export), every trap as WebAssembly.RuntimeError, the CompileError, LinkError and RuntimeError classes, compile and instantiate settling on a later turn, and globalThis.WebAssembly as a value. On 64-bit Linux and macOS, memories sit in 8 GiB guard reservations and a SIGSEGV/SIGBUS handler turns faults into traps or stack exhaustion; async fibers get a guard page on first use. Sanitizer builds and Windows check bounds and the stack explicitly. A WebAssembly.Module crosses to workers through W0's transfer hook (W4). W1's refusals become lowerings; the Memory, Table and Global constructors, Module.imports/exports/customSections and the streaming functions still refuse with SC2020. The globals: WebAssembly compatibility row moves to partial. Evidence: differential corpus programs for the API, TypeScript use and the codemode worker shape, plus five programs executing about 9,300 commands of the WebAssembly 2.0 spec suite; all match Node in the plain and sanitized lanes. quickjs-wasi runs through its own glue, matching Node (apart from a pre-existing non-wasm fence) and on par with or faster than V8. The zero-cost gate leaves every non-wasm program byte-identical. 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.