In today’s web development landscape, it’s essential to optimize our build process to leverage the full potential of modern browsers. One way to achieve this is by utilizing native JavaScript features and minimizing the polyfills included in our bundle.

Rollup.js is a popular JavaScript module bundler that offers several optimizations for our applications. In this article, we’ll explore how we can optimize a Rollup.js build for modern browsers using native JavaScript features.

1. Targeting modern browsers

By targeting only modern browsers, we can exclude unnecessary transpilation and polyfills, resulting in a leaner bundle size. To accomplish this with Rollup.js, we can use the browserslist configuration.

// package.json
{
  "browserslist": "last 2 Chrome versions, last 2 Firefox versions, Safari >= 12, Edge >= 80"
}

By specifying the supported browsers in the browserslist field of our package.json, Rollup.js will only include necessary polyfills based on our browser support matrix.

2. Treeshaking

Treeshaking is a technique used by Rollup.js to eliminate unused code from our bundle. It works by analyzing the module dependency graph and removing any unused exports. To make the most of treeshaking, it’s vital to follow some best practices:

• Use ES modules: Ensure that your project uses ES modules syntax (import/export) instead of CommonJS (require/module.exports) that doesn’t support treeshaking.
• Avoid side-effects: Functions or modules with side-effects, like modifying global state, cannot be safely removed by treeshaking. By writing pure functions and avoiding unnecessary side-effects, we can increase the effectiveness of treeshaking.

3. Minification and compression

Minification and compression are crucial steps in reducing the bundle size. Rollup.js supports several plugins that optimize and compress our code, such as rollup-plugin-terser. It removes unnecessary code, renames variables, and performs other optimizations to reduce the final bundle size.

To use the rollup-plugin-terser, first, install it as a development dependency:

npm install --save-dev rollup-plugin-terser

Then, update your rollup.config.js file to include the plugin:

import { terser } from 'rollup-plugin-terser';

export default {
  input: 'src/index.js',
  output: {
    file: 'dist/bundle.js',
    format: 'esm',
  },
  plugins: [
    terser(), // add terser plugin for minification and compression
  ],
};

By adding the terser plugin to your Rollup.js configuration, your final bundle will be minified and compressed, resulting in a smaller file size.

Conclusion

Optimizing our Rollup.js build for modern browsers by leveraging native JavaScript features can significantly improve the performance and loading times of our web applications. By targeting specific browsers, utilizing treeshaking, and applying minification and compression, we can achieve leaner and faster bundles.

Remember to regularly test your application in various browsers to ensure compatibility. Embracing modern web standards and features can lead to cleaner and more efficient code, providing a better experience for your users.

#webdevelopment #javascript