Malte UblandClaude Opus 5.5 5bcabf9dd5 Lower a finite-literal keyed read over a subset of the declared fields
`filter[resourceType]` where the receiver is a record with several
optional members and the key type is a finite union of literal keys
(`"extensions" | "skills" | ...`) refused with SC1090 whenever the
checker's answer type did not cover every declared field. That is the
common settings-record shape: the key domain names four of the members
and the rest have unrelated types.

The key type is a finite domain, so the read now dispatches over exactly
the fields it can name, comparing the key against each canonical
property spelling. The answer is the join of the reachable fields' types
— precisely the checker's answer type — and a key outside the domain
reads undefined, as a missing property does. Nothing is emitted for a
field the key type cannot name, so no widening to the full record leaks
into downstream lowering.

The dispatch is gated on the shape having no index signature, on the
access not being a call (`o[k]()` keeps its fence for inherited
methods), on the reachable fields being a proper subset, and on the join
holding an undefined arm so a smuggled key has an answer. A key domain
that names every field keeps the single keyed-read helper.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-28 09:37:03 -07:00
2026-10-27 23:21:09 -05:00
2026-10-16 10:33:14 -05:00
2026-10-27 23:21:09 -05:00
2026-10-14 17:27:02 -05:00
2026-10-25 11:26:13 -05:00
2026-07-22 18:08:04 -05:00
2026-10-27 16:45:14 -05:00
2026-10-25 21:21:26 -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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