What is a Module Bundler

A module bundler is a tool used to package many files (modules) into a single or few files that can be loaded efficiently in browsers, basically they organize code to improve performance.

How a Module Bundler Works.

The the series of steps a module bundler takes to bundle code is as follows;

1. It starts by searching for your application’s entry point, usually index.js.
2. Dependencies resolution : the process of analyzing, finding, and connecting all the dependencies (imported modules, libraries, files) that an application needs to work correctly. First, It scans through the entry point file and looks for imports or requires and every file that it depends on. It does this for the dependencies as well until there’s no more and then it creates what is called a dependency graph.

A Dependency Graph is basically a graph that maps the relationships between modules indicating which module depends on which and also helps avoid circular dependencies.

1. Bundling: The bundler then puts all the code in your application and its dependencies into one or fewer bundles that are ready to be loaded by the browser.

Why Bundlers are Useful

Before module bundlers developers had to manually include files in their HTML pages with multiple <script> tags and this resulted in issues like;

1. Lots of HTTP requests.
2. Global scope issues, since all dependencies were added to the HTML page manually all JavaScript files were in the global scope so if two or more files had the same variable names conflicts arise.
3. No dependency management.

The dawn of bundlers provided the means to solve these issues and provide advantages like;

1. Automatic Dependency Management.
2. Fewer HTTP requests
3. Elimination of Global scope issues.
4. Code Splitting: Applications are split into multiple bundles that are loaded only when needed, speeding up initial load time improving performance and providing better code organization.

Examples of Module Bundler.

Popular module bundlers include;

• Webpack
• Rollup
• Vite
• Parcel

What do you think about module bundlers?
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