bun-extractor

Extract embedded JS modules from Bun standalone (bun build --compile) binaries.

Parses the binary's embedded payload, recovers all bundled modules, and rewrites internal /$bunfs/ imports to relative paths so the extracted source is immediately runnable.

Install

npm install @avmc/bun-extractor

CLI

# List embedded modules
npx @avmc/bun-extractor ./my-app --list

# Extract all modules to a directory
npx @avmc/bun-extractor ./my-app -o ./extracted

Options

| Flag | Description | |---|---| | -l, --list | List embedded modules without extracting | | -o, --out <dir> | Extract to a specific directory (default: cwd) | | -h, --help | Show help |

API

import { openBinary } from "@avmc/bun-extractor";
import { readFileSync } from "fs";

const bin = openBinary(readFileSync("./my-app"));

console.log(bin.entryPoint.path);   // e.g. "src/index.js"
console.log(bin.entryPoint.source); // JS with /$bunfs/ imports rewritten

for (const mod of bin.modules) {
  console.log(mod.path, mod.size, mod.loader);
}

openBinary(buffer: Buffer): BunBinary

Parse a Bun standalone binary and return a BunBinary instance.

BunBinary

• modules: Module[] — all embedded modules
• entryPoint: Module — the binary's entry point module

Module

• name: string — full virtual path (e.g. /$bunfs/root/src/foo.js)
• path: string — cleaned path with virtual prefix stripped (e.g. src/foo.js)
• loader: string — js, ts, jsx, tsx, json, css, file, etc.
• format: string — esm, cjs, or none
• isEntry: boolean
• hasSourcemap: boolean
• hasBytecode: boolean
• contents: Buffer — raw bytes (zero-copy view into the binary buffer)
• source: string — decoded JS/TS source with /$bunfs/ imports rewritten to relative paths
• size: number

Supported platforms

Works on Linux, macOS, and Windows binaries. Handles both /$bunfs/ (Linux/macOS) and B:\~BUN\ (Windows) virtual path formats.

Requires Node.js >= 18.

License

MIT