RollupError: Unexpected character '�' (Note that you need plugins to import files that are not JavaScript)

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04-10-2024

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Demystifying the "RollupError: Unexpected character '�'" - A Guide to Importing Non-JavaScript Files

Have you encountered the frustrating "RollupError: Unexpected character '�'" while bundling your project with Rollup? This error often arises when you attempt to import a file that's not a standard JavaScript file, like a CSS file, an image, or a template. This guide will break down the error, provide solutions, and give you a clear understanding of how to handle non-JavaScript imports in your Rollup projects.

Understanding the Problem

Rollup is a powerful module bundler primarily designed for JavaScript. It excels at combining multiple JavaScript modules into a single optimized file. When you encounter the "Unexpected character '�'" error, Rollup is essentially saying: "Hey, I'm expecting JavaScript code, but this file has characters I don't understand!" This is because Rollup, by default, only knows how to process JavaScript.

The Scenario

Let's imagine you have a simple project structure:

my-project/
  |- index.js
  |- styles.css
  |- images/
     |- logo.png

Your index.js file might look like this:

import './styles.css';
import logo from './images/logo.png';

// ... Your JavaScript code ...

Running Rollup on this project would likely result in the error "RollupError: Unexpected character '�'."

The Solution: Rollup Plugins

The solution lies in utilizing Rollup plugins. These plugins extend Rollup's functionality, allowing it to handle various file types beyond JavaScript.

Here's how you can address the error in the scenario above:

1. Install the necessary plugin:

   npm install rollup-plugin-css rollup-plugin-image
   

2. Configure the plugins in your Rollup configuration file (rollup.config.js):

   import css from 'rollup-plugin-css';
   import image from 'rollup-plugin-image';
   
   export default {
     // ... other Rollup configuration options ...
     plugins: [
       css(),
       image(),
     ]
   };
   

3. Run Rollup again:

   rollup -c rollup.config.js
   

Explanation

• rollup-plugin-css handles CSS files, processing them and injecting them into the bundled output.
• rollup-plugin-image takes care of images, allowing you to import them directly in your JavaScript and have them bundled as assets.

Additional Insights

• Plugin Variety: There are numerous Rollup plugins available for handling various file types like:

  • HTML: rollup-plugin-html
  • JSON: rollup-plugin-json
  • Fonts: rollup-plugin-fonts

• Dynamic Imports: For better code splitting and optimization, consider using dynamic imports:

  const imageImport = () => import('./images/logo.png');
  

• Rollup Configuration: You can customize the behavior of plugins through various options within your Rollup configuration file. Consult the plugin documentation for details.

Conclusion

The "RollupError: Unexpected character '�'" is a common hurdle, but with the right Rollup plugins, you can easily manage imports of non-JavaScript files and build a robust and streamlined project. By understanding the problem, choosing the appropriate plugins, and leveraging the flexibility of Rollup, you'll conquer this error and enhance your development process.