In the wake of React—Facebook’s UI library—came Webpack, a simple but awesome module bundler. Module bundlers are just what they are called, they bundle up JavaScript modules into one file. This way, when the client makes a request to your server, it doesn’t have to make multiple requests for static files. Instead, one file is requested, which in some cases, includes your JavaScript bundle and CSS style. This helps optimize load time and makes you more in control as you can choose to include only what you need when you need it.