Chris Tate
2f40bcb8d4
map, filter, take, drop, flatMap, toArray, forEach, reduce, some, every and find compiled only as one chain from arr.values() or arr.entries() that ended in a consuming method. Every other form was refused, and in JavaScript the refusal was thrown at run time. IteratorObject now maps to the generator type. A consuming method over a chain of stages fuses into one loop over the source: a generator driven like for-of, a Map or Set walked live, or an array by index. A stage on its own builds a helper object: a generator over its source that supports next(), for...of, spreads, Array.from and yield*. A for...of whose head is a chain of stages without flatMap runs the stages inside the loop. The source is closed where Node closes it: when take reaches its count, when some, every or find has its answer, when a callback or the loop body throws, when the loop exits early, and before the RangeError of an invalid take or drop budget. It is not closed when it is exhausted or its own next() throws. return() on a helper object before its first next() closes the source through a new runtime hook, scr_gen_set_unstarted_return. When closing an iterator throws while another error propagates, the first error reaches the caller, as in Node. This applies to for...of over a generator too, where the error from the close used to replace the body's error. The try statement takes a dropFinallyErrors flag, whose cleanup handler calls the new scr_exc_keep_first. throw() lowers only on values typed as generators. Iterator helpers and the built-in iterators have no throw method, and a value typed as an iterator may hold one. Callbacks in JavaScript bind their unannotated parameters to the element type, and flatMap callbacks may return generators. A generator whose record yields share checked storage with its return channel has each value converted to the declared element type as it is pulled.
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.