Malte UblandClaude Opus 5.5 efc22a2fd3 Box user module namespaces as dynamic values
A `file:` module namespace handed to typed code now boxes as Node's
namespace object instead of the "converting typed values to 'unknown'"
fence: `const u: unknown = ns`, `take(ns)`, a `Promise<typeof
import("./m")>` widened to `Promise<unknown>` (or `Promise<unknown> |
undefined`), and `await import("./m")` in an `unknown` slot all see one
non-extensible null-prototype object per module whose own properties are
the module's exports in Node's sorted order. They are enumerable
read-only accessors whose reads call the compiled namespace getter, so
they stay live, and the object carries Symbol.toStringTag "Module",
Node's strict-mode write TypeErrors, the not-extensible add error and
the ToPrimitive throw. `node:` builtins have no compiled export table
and keep their SC1101 fence.

The object is built by a new gated runtime unit,
packages/runtime/src/scr_module_namespace_dyn.c, selected by the
`moduleNamespaceDyn` runtime feature (`module.namespaceDyn` in the IR).
It adds no field to ScrDynHandleOps and no branch to a shared unit: the
core reaches it through the ordinary SCR_DYN_OBJ paths, so key listing,
for-in, `in`, JSON, identity, property reads and assignment all reuse
the existing dispatch. The compiler reuses the getter lifted for
module.namespaceValue (existing programs' IR is unchanged) and adds
moduleNamespacePromiseDynValue, one lifted async mapper per module for
the promise slots.

Zero cost: a program that never boxes a namespace links exactly what it
did. The zero-cost gate reports every program identical, with
byte-identical IR and LLVM; the runtime pack's only difference is the
new unit (0 changed runtime functions), and among the namespace corpus
programs only 8412 links it.

Evidence: tests/corpus/8412-module-namespace-untyped is a differential
program against Node in both the plain and sanitized lanes, and the
diagnostics snapshots and TypeScript 7 baselines stay unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-28 05:37:45 -07:00
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2026-07-22 18:08:04 -05:00

scriptc

Vercel Labs Experiment npm version: scriptc License: Apache-2.0 npm downloads per month: 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

Contributing

See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.

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