Introduction

Bun created quite a buzz late last year when v1.0 was released. Unlike NodeJS which uses the V8 engine, Bun uses the JavaScriptCore framework which was created by Apple. The framework is written in C++ and is used in Safari and other Apple products. It’s an all in-one bundler, package manager and runtime, potentially replacing NodeJS.

Here’s a graph breaking down the performance benchmarks of Bun vs Node vs Deno:

As you can see Bun surpasses Node.js and Deno in handling concurrent connections, achieving 110,000 requests per second with 10 concurrent connections, compared to Node.js’s 60,000 and Deno’s 67,000​.

Getting Started with Bun

You can see in the Bun documentation that it’s easy to get started. You can install it with a single command:

    npm install -g bun # the last `npm` command you'll ever need

or if you’re using Homebrew:

    brew tap oven-sh/bun # for macOS and Linux
    brew install bun

Also if you’re a TypeScript user, you can install the type definitions:

    bun add -d @types/bun

Now that you have Bun installed, you can use the CLI to execute any JavaScript/TypeScript file, package.json and other executable files.

    bun run index.js # run a JavaScript file
    bun run index.ts # run a TypeScript file
    bun run package.json # run a package.json file
    bun run # run the main file in package.json

Let’s create our first Bun project. We’ll create a new directory and initialize it with Bun.

    mkdir bun-project
    cd bun-project
    bun init

You can now run the project with bun run or bun run index.js.

Let’s add the package “figlet” to our project. It’s a package that converts text to ASCII art. We’ll add it to our project with the bun add command.

    bun add figlet
    bun add -d @types/figlet # TypeScript users only

Now in our index.ts file, we’ll add the following code:

import figlet from "figlet";

const server = Bun.serve({
  fetch() {
    const body = figlet.textSync("Hot Buns!");
    return new Response(body);
    return new Response("Hot Buns!");
  },
  port: 3000,
});

Now whenever we run bun run index.ts, we’ll see the following output:

    $ bun run index.ts
    Bun is serving at http://localhost:3000

  _   _       _     ____                  _
 | | | | ___ | |_  | __ ) _   _ _ __  ___| |
 | |_| |/ _ \| __| |  _ \| | | | '_ \/ __| |
 |  _  | (_) | |_  | |_) | |_| | | | \__ \_|
 |_| |_|\___/ \__| |____/ \__,_|_| |_|___(_)

You can clone this project from GitHub