Malte UblandClaude Opus 5.5 b767c38e9e Build union spread merges as the checked-dynamic object
`{ ...base, ...override }` over union-typed sources has one field set per
combination of source arms, so the merged value can carry fields from
several arms at once. When the per-arm distribution (slice 1a) cannot pick
one arm, the merge was refused with SC2003 and the site did not compile
(provider-composer's all-optional compat unions, mcp's aggregate config).

Build the object Node builds instead: the checked-dynamic literal, whose
keys are written in source order through the existing dynamic-object path
(field chunks, spreads by copy-data-properties, computed keys by
propertyKey), then converted into the declared union by the existing
checked conversion. Reflection, JSON and inspection see the keys Node
keeps; a value the union cannot hold throws the catchable TypeError at the
conversion rather than being reinterpreted as one arm. The fallback stays
narrow: union-typed spread source, auto tier, no capture buffer, and a
union the checked extraction can validate — everything that compiles
today lowers exactly as before, and `--tier=static-only` keeps the refusal
that tests/diagnostics/union-spread-merge.ts pins.

Corpus union-spread-merge.ts pins key order, last-writer-wins, nested
identity, the accepting typed consumer and the snapshot semantics
differentially; dyncheck's "union spread merge" covers the refusing
single-arm reinterpretation scriptc-only, since Node never checks a cast.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-29 19:23:44 -07:00
2026-10-29 16:39:31 -05:00
2026-10-16 10:33:14 -05:00
2026-10-29 16:39:31 -05:00
2026-10-14 17:27:02 -05:00
2026-10-29 06:02:00 -05:00
2026-07-22 18:08:04 -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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