How I Published My Rust Bun Version Manager (bum) CLI to NPM Package

Ryan Owen Thionanda — Sun, 07 Dec 2025 04:49:13 +0000

Background

So I built this CLI called bum - a fast Bun version manager written in Rust. Works great locally, but I wanted anyone to just run:

npx @owenizedd/bum use 1.3.3

without installing the bum rust binary or anything. That's going to be freaking awesome right?

Turns out, this is totally possible! I learned about it from this awesome article by lekoarts.de about publishing Rust CLIs on npm using napi-rs.

The Setup
The magic is napi-rs - it compiles your Rust code into native Node.js addons (.node files) for each platform.

Add napi-rs to your Rust project

# Cargo.toml
[lib]
crate-type = ["cdylib", "rlib"]

[dependencies]
napi = "2.16"
napi-derive = "2.16"

[build-dependencies]
napi-build = "2.1"

Wrap your CLI in a napi function

/ src/lib.rs
use napi_derive::napi;

#[napi]
pub fn run(args: Vec<String>) -> napi::Result<()> {
    let rt = tokio::runtime::Runtime::new()
        .map_err(|e| napi::Error::from_reason(format!("Failed to create runtime: {}", e)))?;

    // Your CLI logic here
    rt.block_on(async {
        // run_commands(args).await
    });

    Ok(())
}

Create a simple bin.js

#!/usr/bin/env node

const { run } = require("./index");
const args = process.argv.slice(2);

try {
  run(args);
} catch (e) {
  console.error(e);
  process.exit(1);
}

Configure package.json

{
  "name": "@owenizedd/bum",
  "bin": "bin.js",
  "napi": {
    "name": "bum",
    "triples": {
      "defaults": true,
      "additional": [
        "aarch64-apple-darwin",
        "x86_64-apple-darwin",
        "x86_64-unknown-linux-musl",
        "aarch64-unknown-linux-gnu"
      ]
    }
  }
}

The Challenges

OpenSSL Cross-Compilation Hell
Linux Docker builds kept failing with OpenSSL errors. The fix? Use pure Rust alternatives:

Use rustls instead of native-tls

reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls"] }

Use pure Rust zip compression

zip = { version = "1.1", default-features = false, features = ["deflate"] }

Platform Package Versions Not Syncing

Each platform (darwin-arm64, linux-x64-gnu, etc.) is published as a separate npm package. We forgot to update their package.json versions, so npm couldn't find them!

Fixed by adding a CI step:

- name: Sync platform package versions
  run: |
    VERSION=$(node -p "require('./package.json').version")
    for dir in npm/*/; do
      node -e "
        const fs = require('fs');
        const pkg = JSON.parse(fs.readFileSync('$dir/package.json'));
        pkg.version = '$VERSION';
        fs.writeFileSync('$dir/package.json', JSON.stringify(pkg, null, 2));
      "
    done

Bun Bundling Breaking Everything

Initially we used bun build bin.ts to compile TypeScript. Bad idea - Bun inlined require('./index') and hardcoded the .node filename with a hash!

// Bun bundled this (broken):
`nativeBinding = require("./bum.darwin-arm64-7xvffnqw.node");`

// Should be (working):
`nativeBinding = require("./bum.darwin-arm64.node");`
Solution: Just use plain JavaScript for bin.js. No bundling needed.

Now anyone can run:

npx @owenizedd/bum use 1.3.3

And it just works on macOS, Linux, and Windows (Hopefully! not fully tested yet in other platform just on my Macbook😅 )

Honestly, there might be still a lot of issues, this progress made me so happy so far. Opus 4.5 has made this possible fast as well.

Resources

Publishing a Rust CLI on npm - The article that made this possible
napi-rs Documentation
bum GitHub Repository

Bum - Bun Version Manager

Ryan Owen Thionanda — Sun, 15 Oct 2023 09:14:53 +0000

A lightning-fast Bun version manager written in Rust. ⚡

Check out the Bum Repo

Installation

Getting started with Bum is a breeze. Follow these simple steps to install Bum on your system:

Open your terminal and execute the following command:
curl -fsSL https://github.com/owenizedd/bum/raw/main/install.sh | bash

It will install Bun automatically if you don't have one.

Bum supports both Linux x86_64 and Darwin x86_64 (Mac OS) - For now.
To determine your system architecture, you can run uname -ms in your terminal.

After the installation is complete, restart your terminal, or run the appropriate command to reload your shell configuration:

For Zsh users:
source ~/.zshrc
For Bash users:
source ~/.bashrc

Now if everything done properly, you can start using Bum from your terminal.

Getting Started

Familiar with NVM? if yes, then you will be able to use Bum immediately.

.bumrc File: If you have a .bumrc file in your project directory, Bum will automatically use the version specified in that file when you run bum use without specifying a version.

I do this project as part of my free time, still many exciting improvements to be made.

DEV Community: Ryan Owen Thionanda