What is JavaScript bundling and why does it matter

Short answer

Bundling combines multiple JavaScript files and their dependencies into optimized output files, reducing HTTP requests and enabling transformations like minification and tree shaking.

How it works

A bundler reads the entry point, resolves import statements recursively, applies loaders for non-JS assets, and emits one or more bundles.

Example

// webpack.config.js
module.exports = {
  entry: "./src/index.js",
  output: { filename: "bundle.js", path: __dirname + "/dist" }
};

Why it matters

• Fewer network requests improve load times.
• Tree shaking removes unused code.
• Transpilation ensures compatibility with older browsers.
• Code splitting loads routes on demand.

Common issues

• Misconfigured loaders cause import errors for CSS or images.
• Large bundles hurt initial load; use code splitting and lazy loading.