Bundling Your Code with Bun

Oct 13, 2025 by wbrum.org 32 views

Introduction

Server-side rendering (SSR) is a technique used in web development to render HTML on the server instead of the client. This approach has several benefits, including improved SEO, faster page loads, and better accessibility. In this article, we will explore how to properly implement SSR with Bun, a modern JavaScript bundler, and serve index.html as a starting point.

What is Bun?

Bun is a fast and lightweight JavaScript bundler that allows you to bundle your code and dependencies quickly and efficiently. It is designed to work seamlessly with modern JavaScript features, including ES modules, async/await, and more. Bun is also highly customizable, making it an excellent choice for developers who want to fine-tune their build process.

Setting Up Your Project

To get started with SSR and Bun, you will need to set up your project structure. Create two folders: client and server. Inside the client folder, create a new file called index.html. This file will serve as the starting point for your application.

<!-- client/index.html -->
<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="styles.css">
  </head>
  <body>
    <div id="root"></div>
    <script src="bundle.js"></script>
  </body>
</html>

In the server folder, create a new file called server.js. This file will contain the server-side code for your application.

// server/server.js
import { createServer } from 'bun';
import { renderToString } from 'react-dom/server';
import App from './App';
const server = createServer();
server.get('/', (req, res) => {
const markup = renderToString(<App />);
res.write(    &lt;!DOCTYPE html&gt;     &lt;html&gt;       &lt;head&gt;         &lt;link rel=&quot;stylesheet&quot; href=&quot;styles.css&quot;&gt;       &lt;/head&gt;       &lt;body&gt;         &lt;div id=&quot;root&quot;&gt;${markup}&lt;/div&gt;         &lt;script src=&quot;bundle.js&quot;&gt;&lt;/script&gt;       &lt;/body&gt;     &lt;/html&gt;  );
res.end();
});
server.listen(3000, () => {
console.log('Server listening on port 3000');
});

Implementing SSR with Bun

To implement SSR with Bun, you will need to use the renderToString function from react-dom/server. This function takes a React component as an argument and returns the rendered HTML as a string.

In the server folder, create a new file called App.js. This file will contain the React component that will be rendered on the server.

// server/App.js
import React from 'react';
const App = () => {
return <div>Hello World!</div>;
};
export default App;

In the server folder, create a new file called index.js. This file will contain the entry point for your server-side code.

// server/index.js
import { createServer } from 'bun';
import { renderToString } from 'react-dom/server';
import App from './App';
const server = createServer();
server.get('/', (req, res) => {
const markup = renderToString(<App />);
res.write(    &lt;!DOCTYPE html&gt;     &lt;html&gt;       &lt;head&gt;         &lt;link rel=&quot;stylesheet&quot; href=&quot;styles.css&quot;&gt;       &lt;/head&gt;       &lt;body&gt;         &lt;div id=&quot;root&quot;&gt;${markup}&lt;/div&gt;         &lt;script src=&quot;bundle.js&quot;&gt;&lt;/script&gt;       &lt;/body&gt;     &lt;/html&gt;  );
res.end();
});
server.listen(3000, () => {
console.log('Server listening on port 3000');
});

Bundling Your Code with Bun

To bundle your code with Bun, you will need to create a new file called bun.config.js. This file will contain the configuration for your build process.

// bun.config.js
module.exports = {
  input: 'client/index.js',
  output: 'bundle.js',
  plugins: [
    bun({
      target: 'esm',
      format: 'esm',
    }),
  ],
};

Running Your Application

To run your application, navigate to the server folder and execute the following command:

bun run server/index.js

This will start the server and render the App component on the server. The rendered HTML will be sent to the client, where it will be rendered as a static HTML file.

Conclusion

In this article, we explored how to properly implement SSR with Bun and serve index.html as a starting point. We created a new project structure, set up our server-side code, and implemented SSR using the renderToString function from react-dom/server. We also bundled our code with Bun and ran our application. With this knowledge, you can now implement SSR with Bun and serve index.html as a starting point for your web applications.

Additional Resources

Example Use Cases

E-commerce Website: Implement SSR with Bun to render product pages on the server, improving page load times and SEO.
Blog Website: Use SSR with Bun to render blog posts on the server, improving page load times and accessibility.
Single-Page Application: Implement SSR with Bun to render the initial HTML on the server, improving page load times and SEO.
Q&A: Implementing SSR with Bun and Serving Index.html as a Starting Point ====================================================================

Q: What is Server-Side Rendering (SSR) and why is it important?

A: Server-Side Rendering (SSR) is a technique used in web development to render HTML on the server instead of the client. This approach has several benefits, including improved SEO, faster page loads, and better accessibility. SSR is particularly useful for applications that require high performance and scalability.

Q: How does Bun fit into the picture when it comes to implementing SSR?

A: Bun is a modern JavaScript bundler that allows you to bundle your code and dependencies quickly and efficiently. It is designed to work seamlessly with modern JavaScript features, including ES modules, async/await, and more. Bun is also highly customizable, making it an excellent choice for developers who want to fine-tune their build process.

Q: What are the benefits of using Bun for SSR?

A: Some of the benefits of using Bun for SSR include:

Improved performance: Bun's fast and lightweight architecture makes it an excellent choice for applications that require high performance.
Better scalability: Bun's modular design makes it easy to scale your application as needed.
Improved SEO: By rendering HTML on the server, you can improve your application's SEO and make it more accessible to search engines.

Q: How do I set up my project structure for SSR with Bun?

A: To set up your project structure for SSR with Bun, you will need to create two folders: client and server. Inside the client folder, create a new file called index.html. This file will serve as the starting point for your application. In the server folder, create a new file called server.js. This file will contain the server-side code for your application.

Q: What is the role of the `renderToString` function in SSR with Bun?

A: The renderToString function is used to render React components on the server. It takes a React component as an argument and returns the rendered HTML as a string. This function is used to render the initial HTML on the server, which is then sent to the client.

Q: How do I bundle my code with Bun for SSR?

A: To bundle your code with Bun for SSR, you will need to create a new file called bun.config.js. This file will contain the configuration for your build process. In this file, you will need to specify the input and output files, as well as any plugins you want to use.

Q: What are some common pitfalls to avoid when implementing SSR with Bun?

A: Some common pitfalls to avoid when implementing SSR with Bun include:

Not properly configuring the bun.config.js file: Make sure to specify the correct input and output files, as well as any plugins you want to use.
Not using the renderToString function correctly: Make sure to use the renderToString function to render React components on the server.
Not handling errors properly: Make sure to handle errors properly on the server to prevent crashes and improve user experience.

Q: What are some best practices for implementing SSR with Bun?

A: Some best practices for implementing SSR with Bun include:

Using a consistent naming convention: Use a consistent naming convention throughout your project to make it easier to maintain and scale.
Using a modular design: Use a modular design to make it easier to scale your application as needed.
Testing thoroughly: Test your application thoroughly to ensure that it works as expected.

Q: What are some resources for learning more about SSR with Bun?

A: Some resources for learning more about SSR with Bun include:

Bun Documentation: The official Bun documentation provides a comprehensive guide to using Bun for SSR.
React Documentation: The official React documentation provides a comprehensive guide to using React for SSR.
Server-Side Rendering with React: This article provides a comprehensive guide to implementing SSR with React.

Conclusion

In this Q&A article, we explored some common questions and answers related to implementing SSR with Bun and serving index.html as a starting point. We covered topics such as the benefits of using Bun for SSR, setting up project structure, and common pitfalls to avoid. We also provided some best practices and resources for learning more about SSR with Bun. With this knowledge, you can now implement SSR with Bun and serve index.html as a starting point for your web applications.