Module bundlers are tools used in modern JavaScript development to manage dependencies between files and modules of code. They help organize and package together all the necessary code and assets for a web application, making it easier to distribute, load, and run in a browser.

Module bundlers work by taking all the individual files and modules of code in your project and combining them into a single file or bundle. This bundle can then be easily loaded and executed by the browser.

One of the main benefits of using a module bundler is that it helps manage dependencies between files and modules. If you have multiple files that depend on each other, a module bundler will ensure that all the necessary dependencies are included in the final bundle, reducing the amount of code that needs to be loaded by the browser.

There are several popular module bundlers available for modern JavaScript development, including Webpack, Parcel, Rollup, and Gulp. Each of these tools has its own features and capabilities, so it's important to choose one that fits your specific needs and requirements.

For example, Webpack is a powerful and feature-rich module bundler that is commonly used for large-scale web applications. It supports a wide range of plugins and loaders, making it easy to customize and extend for your specific use case. Parcel, on the other hand, is a lightweight and fast module bundler that is well-suited for smaller projects or rapid development.

Overall, module bundlers are an important tool in modern JavaScript development, as they help manage dependencies between files and modules of code, making it easier to organize, package, and distribute your web application.