An introduction Bun, the evolution of Node.js

3 min readFeb 24, 2023

Bun is a modern JavaScript runtime that comes with a native bundler, transpiler, task runner, and npm client built-in. Developed in the Zig programming language, Bun focuses on speed and performance, using the JavaScriptCore engine instead of V8 used by Node.js and Deno. In this article, we will discuss the top 7 features of Bun, including native TypeScript support, and provide code examples to get started.

Fast and Performant Bun is designed to start fast, with a focus on performance, providing new levels of speed and extending the JavaScriptCore engine. This makes it a great choice for building web applications and high-performance APIs.
All-in-One Solution Bun comes with everything you need to bundle, transpile, install, and run your JavaScript and TypeScript projects. Its built-in npm client allows you to easily manage your dependencies without the need for external tools.
Native TypeScript Support Bun provides native TypeScript support, allowing you to write TypeScript code and compile it to JavaScript without the need for an external tool like the TypeScript compiler. Here’s an example of compiling TypeScript code using Bun:

bun build src/index.ts

4. WebSocket Support Bun has built-in WebSocket support, making it easy to build real-time applications and chatbots. Here’s an example of creating a WebSocket server using Bun:

import { WebSocket } from 'bun';

const server = new WebSocket.Server({ port: 8080 });

server.on('connection', (socket) => {
  socket.on('message', (message) => {
    console.log(`Received message: ${message}`);
    socket.send(`You said: ${message}`);
  });
});

5. Server-side Rendering with React Bun provides built-in support for server-side rendering with React, making it easy to build highly performant web applications with React. Here’s an example of server-side rendering with React using Bun:

import { renderToString } from 'react-dom/server';
import App from './App';

bun.http((req, res) => {
  const html = renderToString(<App />);

  res.send(`
    <html>
      <body>
        <div id="app">${html}</div>
        <script src="/bundle.js"></script>
      </body>
    </html>
  `);
});

6. SQLite Support Bun has built-in support for SQLite, a lightweight relational database management system. Here’s an example of using SQLite with Bun:

import { SQLite } from 'bun';

const db = new SQLite(':memory:');

db.query(`
  CREATE TABLE users (
    id INTEGER PRIMARY KEY,
    name TEXT NOT NULL,
    email TEXT NOT NULL
  )
`);

db.query(`
  INSERT INTO users (name, email)
  VALUES ('John Doe', 'john.doe@example.com')
`);

const users = db.query(`
  SELECT * FROM users
`);

console.log(users);

7. Easy Installation and Setup Bun is easy to install on Mac and Linux with a simple command:

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

Once installed, you can create a new Bun project with the bun init command:

mkdir myproject
cd myproject
bun init

This will create a new Bun project with a default configuration and a simple example file.

In conclusion, Bun is a powerful JavaScript runtime with a focus on speed and performance. It comes with built-in support for everything you need to build modern web applications, including native TypeScript support, WebSocket support, server-side rendering with React, and SQLite support. With its easy installation

An introduction Bun, the evolution of Node.js

Written by Max Headway