scriptc README

The project's README from github.com/vercel-labs/scriptc. As one markdown file: README.md.

scriptc

scriptc compiles TypeScript and JavaScript to typed IR, readable C, textual LLVM IR, native assembly and objects, native executables, and WebAssembly modules. It uses the TypeScript compiler for parsing and type checking. Source outputs require only Node. On macOS 15+ arm64, ordinary LLVM-tier executables use scriptc's bundled helper and precompiled runtime pack; clang is only the platform linker driver and does not compile program or runtime C.

Static builds include a small native runtime, but no Node or JavaScript engine. Code that cannot compile statically is reported as a diagnostic. For npm packages and any-typed code, --dynamic embeds quickjs-ng explicitly.

scriptc is experimental and targets macOS, Linux, Windows, and WebAssembly via WASI Preview 1.

Installation

The compiler requires Node.js 24 or newer. --emit=ir|c|llvm needs only Node. --emit=asm|obj uses the matching optional platform helper installed with scriptc on supported macOS, Linux, and Windows hosts (and for WASI), but needs no compiler, archiver, linker, or SDK. Ordinary LLVM-tier executable builds need a platform linker driver and SDK/sysroot, but use the bundled helper plus precompiled runtime pack rather than compiling generated or runtime C. Set SCRIPTC_LINKER to choose that driver. Explicit C builds, LLVM fallbacks, --sanitize, and the deprecated SCRIPTC_CC=clang|zigcc compatibility route additionally need a C compiler. The executables it produces do not require Node.

$ npm install -g scriptc

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 ctate
hello, ctate

Or stop at a source-level compiler artifact without invoking clang, an archiver, or a linker:

$ scriptc build hello.ts --emit=ir >/dev/null
$ ls .scriptc/
hello.ir.json
$ scriptc build hello.ts --emit=c >/dev/null
$ ls .scriptc/
hello.c
$ scriptc build hello.ts --emit=llvm >/dev/null
$ ls .scriptc/
hello.ll
$ scriptc build hello.ts --emit=asm >/dev/null
$ ls .scriptc/
hello.s
$ scriptc build hello.ts --emit=obj >/dev/null
$ ls .scriptc/
hello.o

--emit=obj writes a relocatable program object, not a standalone library. It has undefined scr_* runtime references and a required scr_runtime_abi_v1 marker; scriptc build --lib --profile ... remains the self-contained archive interface. The helper runs on macOS 15+ arm64 and emits artifacts with an arm64-apple-macosx14.0.0 deployment target. Sanitized assembly/object emission is rejected until the helper's AddressSanitizer pipeline matches the executable path.

External object consumption is experimental. Use --print=native-link-info to emit the object and print a versioned JSON recipe containing its target, main entry, exact @scriptc/runtime source pack, required system libraries, FFI inputs, and ABI marker. The recipe never uses hidden scriptc cache paths. See examples/native-object for C-driver and direct Apple-linker builds.

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

Check static coverage

scriptc coverage shows how much of a program can compile statically and gives a coded diagnostic for every dynamic or unsupported site.

$ scriptc coverage hello.ts

  statements analyzed   2
  compile statically    2  (100%)

  fully static — this program has no dynamic remainder.

Build WebAssembly

WASI and other cross-target builds require Zig. Its bundled WASI libc produces a portable WASI Preview 1 module through the production LLVM backend:

$ SCRIPTC_CC=zigcc SCRIPTC_TARGET=wasm32-wasi scriptc build hello.ts --no-keep-c -o hello.wasm >/dev/null
$ file hello.wasm
hello.wasm: WebAssembly (wasm) binary module version 0x1 (MVP)
$ SCRIPTC_CC=zigcc SCRIPTC_TARGET=wasm32-wasi scriptc run hello.ts
hello, world

The WASI target supports the same executable language tiers as the native targets, including async/await, promises, generators, timers, stdin/readline events, callback and promise filesystem APIs, and --dynamic. APIs that require capabilities absent from portable WASI Preview 1—network sockets/fetch, child processes, OS signals, and filesystem watching—fail before linking with SC3002; sanitizer builds, native FFI, and library-mode archive builds are target diagnostics too. See platform support for the precise boundary.

Use npm packages

Pass --dynamic to embed an npm package's JavaScript in the executable. The result does not read node_modules at runtime.

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

Documentation

See the quickstart and CLI reference for the complete workflow. The docs also describe npm dependencies, native FFI, platform support, and the current limitations.

Development

$ pnpm install && pnpm -r build
$ vercel link && vercel env pull  # writes a project-scoped VERCEL_OIDC_TOKEN
$ pnpm test:sandbox

The normal workspace build needs no local LLVM installation. To rebuild a native helper/runtime pack, install CMake, Ninja, and the pinned LLVM 22 development package on that target host, then run the matching @scriptc/llvm-<platform> and @scriptc/runtime-<platform> build:native scripts. The macOS full test suite also uses those generated artifacts.

pnpm test:sandbox loads .env.local, preflights Vercel authentication and project access, and uses the managed vercel/sandbox/universal image by default. It installs the repository-pinned Node, pnpm, and LLVM toolchain plus ScriptC dependencies in each disposable Sandbox before building the uploaded worktree. Set SCRIPTC_SANDBOX_IMAGE to a fully qualified VCR reference only to use the optional prebuilt image from pnpm test:sandbox:image. The prebuilt image keeps the roughly four-minute fast path; cold managed-image runs take longer because they install the pinned toolchain in each Sandbox.

VERCEL_OIDC_TOKEN is preferred. For access-token authentication, set VERCEL_TOKEN, VERCEL_TEAM_ID, and VERCEL_PROJECT_ID; team and project are never inferred from SCRIPTC_SANDBOX_IMAGE. The legacy VCR command used by pnpm test:sandbox:image cannot authenticate with an OIDC JWT, so image builds use VERCEL_TOKEN when available or the existing Vercel CLI login; OIDC claims still select the VCR team and project. The test corpus runs each program under Node and as a compiled native binary, then compares stdout, stderr, and exit codes byte for byte. The full gate also runs the corpus with AddressSanitizer and the runtime reference-count audit.

scriptc (vercel-labs/scriptc)

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6.1K ·GitHub
Scriptc
What is this?scriptc is an experimental compiler that turns TypeScript and JavaScript into typed IR, readable C, LLVM IR, native assembly/objects, native executables, or WebAssembly modules, producing standalone binaries that do not need Node.js to run.
Is this a transpiler like tsc, or does it actually produce native binaries?It goes beyond transpiling to JS: scriptc uses the TypeScript compiler only for parsing and type checking, then emits native executables with a small bundled runtime (no Node or JS engine needed), or WebAssembly modules via WASI.
How do I compile a program with it?Write a .ts file, then run scriptc with --emit=ir|c|llvm|asm|obj to get an intermediate artifact, or build a standalone executable directly; `scriptc build --lib --profile ...` creates a self-contained archive.
What do I need installed besides Node?Node.js 24+ is required for everything. --emit=ir|c|llvm needs only Node; --emit=asm|obj uses scriptc's bundled platform helper with no extra compiler needed; full executables need a platform linker driver/SDK (set via SCRIPTCLINKER); WebAssembly/WASI builds additionally require Zig.
Does it support every TypeScript or JavaScript feature out of the box?No - code that cannot compile statically is flagged as a diagnostic, and any-typed code or npm packages need the --dynamic flag, which embeds the quickjs-ng engine. WASI builds also reject anything needing sockets, child processes, OS signals, or filesystem watching.
Which platforms and targets does it support?scriptc targets macOS, Linux, and Windows for native builds, plus WebAssembly via WASI Preview 1; the bundled LLVM-tier helper currently runs on macOS 15+ arm64.
What does the --dynamic flag do?It embeds the quickjs-ng JavaScript engine in the output so the compiler can fall back to interpreting any-typed code or an npm package's JavaScript inside the native binary, without reading node_modules at runtime.
How do I check how much of my code can compile statically?Run scriptc coverage - it reports how much of a program compiles statically and prints a coded diagnostic for every dynamic or unsupported call site.
What is --print=native-link-info for?It emits the compiled object and prints a versioned JSON recipe describing the target, main entry, exact runtime package version, required system libraries, FFI inputs, and ABI marker, which is useful for custom linking setups.
Why does WebAssembly output need Zig instead of the bundled helper?Cross-target WASI/WebAssembly builds go through Zig's bundled WASI libc and LLVM backend to produce a portable WASI Preview 1 module, a different toolchain path from the native macOS/Linux/Windows helper.
What are similar projects?CalcKernel, emscripten, compiler, perry, GoodmansKernel, tsx, goose, assemblyscript
Which topics is it in?clang, zig, llvm, transpiler, toolchain, assembly, runtime, vercel, webassembly, systems-programming, native, static-analysis
Creator
vercel-labs
Size
69.8 MB
Stars
6.1K
Updated
CommitOct 17Releasev0.3.5Oct 16
Age
2mo
Commits · 90 Days