Bun.js Env Setup

🌱 Introduction to Environment Setup in Bun.js

Setting up your environment correctly is crucial when working with any modern JavaScript runtime, and Bun.js is no exception. Bun offers fast performance, a powerful runtime, and developer-friendly tooling.

This tutorial will walk you through how to set up a clean development environment for building applications using Bun.js.

📦 Prerequisites

Before you get started, ensure you have the following:

• Operating System: macOS, Linux (Windows support is still evolving)
• Terminal or command-line access
• Basic understanding of JavaScript

⚙️ Installing Bun.js

Bun provides a very simple installation command. You can install it via curl:

curl -fsSL https://bun.sh/install | bash

This script will install the latest version of Bun and configure your shell automatically.

Restart your terminal session to apply changes.

🔍 Verifying Installation

To check if Bun was installed successfully, run the following command:

bun --version

If everything worked, it should output the installed version of Bun.

📁 Creating a Project

You can create a new Bun project using:

bun init

This will prompt you with a few questions and create a basic project with the right structure. It will include:

• index.ts or index.js
• package.json
• bun.lockb

🔧 Managing Environment Variables

Like Node.js, Bun also supports environment variables. To manage sensitive or configuration-based values, use a .env file in the root of your project.

# .env
API_KEY=abc123
ENV=development

You can access these variables in your code using process.env:

console.log("API Key:", process.env.API_KEY);

🪄 Auto Reload with Watch Mode

Bun doesn’t support hot reloading out-of-the-box like some tools, but you can enable auto-restart by running:

bun --watch index.ts

This is useful when making rapid code changes and testing behavior instantly.

🛠️ Setting Up Scripts in package.json

To make your workflow easier, you can define scripts in package.json:

"scripts": {
  "start": "bun index.ts",
  "dev": "bun --watch index.ts"
}

Now you can run bun run dev to automatically restart your app on file changes.

📌 Installing Dependencies

Bun comes with its own ultra-fast package manager. You can install any package like this:

bun add axios

It will automatically update your package.json and generate a bun.lockb file to track dependencies.

🚀 Final Thoughts

Setting up your environment with Bun.js is fast and smooth, thanks to its all-in-one ecosystem. From dependency management to file watching and environment variables, Bun provides everything you need to get started with full-stack JavaScript development.

Ready to build blazing fast apps? Start with Bun and experience the future of JavaScript tooling!