Solved: find the unused npm modules

Finding unused npm modules is a common challenge faced by developers in the JavaScript ecosystem. This is especially relevant in big projects where removing unnecessary dependencies can heavily reduce the bundle size and increase the application’s performance. In this detailed guide, we’ll comprehensively explain how to identify and remove these unused npm modules.

Understanding npm Modules

Before diving into solutions, it’s important to gain a clear understanding of npm modules. npm is the world’s largest software registry, containing over 800,000 code packages. These packages or modules, are open-source and shared by developers globally.

Every JavaScript project has a unique set of npm modules that developers add over time to simplify and speed up their work. However, as projects grow, it’s common to lose track of these dependencies. Over time, our projects end up with unused npm modules which are just taking up space and slowing down application speed.

The Importance of Cleaning Unused npm Modules

Unused npm modules are like extra luggage that your app carries around. The extra weight can slow down your load times and, in some cases, lead to security vulnerabilities. This makes cleaning unused npm modules a crucial task for optimizing your app’s performance.

Given the importance of this task, several tools have come into existence that help in identifying and removing these unnecessary dependencies. One such tool that we’ll be discussing is Depcheck.

The Solution: Using Depcheck

Depcheck is an npm package developed specifically for detecting unused dependencies in your project. To start looking for unused dependencies in your project follow these steps:

npm install -g depcheck

These commands will do the following: the first command will install Depcheck globally on your system. The second command when run, it will begin scanning your project for unused dependencies.

Understanding the Results

Depcheck provides a result in JSON format. It typically has three properties:

  • dependencies: List of unused dependencies.
  • devDependencies: Specifies unused devDependencies.
  • missing: Shows missing dependencies, i.e., dependencies used in the code but not in package.json.

Here is an interpretation of the results that you can use to optimize your project.

Moving Forward

After identifying unused npm modules, it’s time to remove them. You can do this manually by updating your package.json, or use npm uninstall command followed by the packages you want to remove.

Keeping a clean project with only the necessary dependencies is a good practice for every developer. It will help you reduce your bundle size, increase your app performance and avoid potential security vulnerabilities.


Keeping track of your npm modules and optimizing your app’s performance by removing unused ones can be a daunting task. Fortunately, tools like Depcheck make it significantly easier for developers to manage their dependencies.

Remember that cleaning up your dependencies is an ongoing process. Keep an eye on your dependencies, and make sure you’re actively removing unnecessary ones. With the best practices and tools discussed in this guide, you’ll have a lean, efficient and secure project.

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