Every release that left a headered object alive and unbuffered called scr_cyc_on_release, which looked up the type's bypass statistics, pushed the object, kept a running total and compared it with two triggers. The nursery case now has a fast path that appends the object to the nursery buffer itself, while the runtime-maintained window says the append can neither make a collection due nor grow the buffer, and the live count is below the allocation trigger: - scr_rc.h exports the candidate buffers (scr_cyc_buffers: the three buffers, the window and the allocation trigger) where the collector state is ordinary globals, and scr_cyc_append. The runtime's own release paths (scr_cyc_released) append inline, and scr_cyc_on_release tries the append first. - Optimized emitted code buffers through one sc_cyc_append helper per module, called with preserve_mostcc, so release fast paths keep the size of the plain call they had (inlining the append into every release fast path grew the self-hosted compiler's text by 4.6%) and their callers keep their registers. Its runtime call goes through a second preserve_mostcc function, which keeps the register saves off the append path. - scr_cycle.c keeps the window: recomputed where buffers, capacity or the trigger change in bulk, lowered by one on older buffering and nursery deaths, 0 during passes. The running total is gone; the slow path sums the buffers. - An appended candidate whose type bypasses the nursery would have been buffered past it. scr_cyc_route_bypassed moves such candidates before any scheduling decision or pass reads the buffers, consuming the bypass counts as scr_cyc_on_release does (skipped while no type bypasses). test_cycle checks the window (the release that reaches the trigger still collects) and the routing of inline-buffered candidates of a bypassed type; its mature-bypass probe routes before reading generations. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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
- Introduction: what scriptc is and what you can build.
- Quickstart: installation and your first executable.
- Coverage reports: check whether an existing program compiles.
- Platform support: cross-compilation and WebAssembly.
- CLI reference: commands, options, and output formats.
- Native program objects: use compiler output in external builds.
- Native FFI: call C ABI functions from compiled programs.
- WebAssembly modules: build and embed WASI modules.
- Examples: programs and integration examples in this repository.
Contributing
See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.