Malte Ubl af7a1bdfed Skip null slots in emitted trace functions
Emitted class and record trace functions passed every traced slot to the
visitor, empty ones included, and the visitor's first test dropped them.
Most traced slots of a large heap are empty (optional links, unset caches):
in tsc-ts, 56% of the child edges the nursery's markGray visited were null
(Excalidraw 18.5M of 33M per single-threaded run, Sentry 111M of 210M), and
full passes visited about as many. Each was an indirect call, and the
restoring scan made it again.

Trace functions now test each loaded slot and skip the call for null. Every
collector visitor already ignores null children and the collector is the
only caller of trace functions, so what a pass walks is unchanged.

tsc-ts (Linux sandbox, interleaved, 5 rounds, medians): single-threaded
Excalidraw -2.6%, TypeORM -2.4%, self-check -2.0%; --checkers 8 -8.6%,
-8.2%, -3.3%. Peak RSS within +-1%. tsc-ts binary +20,408 bytes (+0.09%).
2026-10-11 09:38:28 -07:00
2026-07-22 18:08:04 -05:00
2026-10-10 10:08:39 -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 TypeScript's type information to compile supported code to native instructions. Static builds run without Node.js or a JavaScript engine.

For npm dependencies and any-typed code, enable --dynamic to include the embedded quickjs-ng engine. Dependency JavaScript is included at build time.

scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. See the limitations and Node.js compatibility reference before using it for an existing project.

Installation

Install with Node.js 24 or later and npm:

$ npm install -g scriptc

The installed compiler runs natively on supported macOS, Linux, and Windows hosts. Native compilation and execution do not require Node.js. Standalone compiler archives are also available from GitHub Releases.

Executable builds require a platform linker and SDK/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}`);

Compile and run it in one step:

$ scriptc run hello.ts
hello, world

Or write a standalone executable:

$ scriptc build hello.ts -o hello
$ ./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 which operations compile statically, require dynamic execution, or are unsupported. 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
$ ./server
listening on http://localhost:8080

Use npm packages

Pass --dynamic to embed an npm package's JavaScript in the executable. The result does not 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 --dynamic -o cli
$ ./cli
hello from scriptc

Enabling --dynamic does not add support for unsupported statically typed calls. See npm dependencies for package resolution and the boundary between static and dynamic code.

Documentation

Contributing

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

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