A record literal asserted to a wider record type (`{ truncated: true }
as TruncationResult`) is a checked cast whose source shape lacks some of
the target's fields. Slice C1 of the presence-narrowing design: teach the
record-view plan, the LLVM backend and the runtime about the PARTIAL view
such a cast answers.
- `dynCheck.partialView` marks the cast; the validator requires a
`dynFrom{liveRef}` record operand whose every field is a target field
with an equal type.
- `planRecordViews` records the (target, source) pairs it cannot plan as
full views and exposes `partial`, `partialTargets` and
`partialMissing`; the cycle analysis owns these views like the rest.
- `recordViewCall` emits the `SIZE_MAX` sentinel for a target field the
source does not declare.
- `scr_record_view_slot` answers NULL for a field the viewed record does
not declare (its offset table holds `SIZE_MAX`), and
`scr_record_view_field` passes that answer through. The emitted view
guard, the clone helper and a presence test (`recordHas`) ask for that
slot and stop with `scr_trap` and the program's own message when it is
absent, so the runtime gains no string constant and no function: a new
function in a linked unit shifts the pack for every program. A program
without a partial assertion compiles to the same bytes.
- `recordHas` asks the view when the field is missing from some partial
source, and still honors an undefined-armed field.
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.