Malte UblandClaude Opus 5.5 eb998d4f4d Key class fields and methods by symbols from CommonJS key tables
A JavaScript package often keeps its private symbols in one module,
`module.exports = { kClosed: Symbol('closed'), ... }`, and its classes
declare `[kClosed] = false` fields and `[kDispatch]()` methods with keys
destructured from that table (undici's core/symbols.js). Those keys were
not stable, so every such class was rejected, and with it every subclass
in other modules ("extending classes not declared in the program").

A property of a JS module's effective top-level `module.exports = {...}`
literal initialized with `Symbol(<constant>)` or `Symbol.for(<constant>)`
is now a stable class key, as a module-scope const is, provided nothing
before the table can run code (a require there could close a cycle and
publish the empty initial exports object), no earlier property can run
code, and nothing writes the property or replaces it through `exports`.
The property's own declaration symbol is the identity every requirer
shares, and the table's export global supplies the runtime key for
dynamic lookups (a base method calling a subclass's symbol-keyed method).

The checker types such keys as plain `symbol`, so it answers `this[k]`
with the union of every symbol-keyed property of the class. Reads through
table keys in JS files now take the field's own layout type.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-19 13:18:13 -07:00
2026-10-18 09:55:59 -05:00
2026-10-16 10:33:14 -05:00
2026-10-18 17:47:55 -05:00
2026-10-14 17:27:02 -05:00
2026-10-17 13:47:41 -05:00
2026-07-22 18:08:04 -05:00
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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