ndu - Visualize your Node app's disk space usage

Requires node 4+ and du. Windows not yet supported.

ndu is a tool for analyzing the size of dependencies in a node.js application. It's similar to disc, but for server-side dependencies instead of client-side depedencies.

When building node.js apps, you can choose from hundreds of thousands of libraries available on npm. But sometimes these libraries contain many hidden sub-dependencies that bloat the size of your application. This tool helps you identify which modules are bringing in the bloat. It's very useful when you're wondering why your seemingly simple node app takes up hundreds of MBs of space on disk.

Installation

Install from npm:

npm install --global ndu

Usage

Simply run ndu in the root folder of your node.js application.

By default it will write an HTML file with the results to stdout:

ndu > ndu.html && open ndu.html

Just like disc, ndu can also open the result directly in a browser:

ndu --open

Example

First, let's create a very simple web app using express-generator:

$ npm install -g express-generator
$ express example-web-app
$ cd example-web-app/
$ npm install

Now we have a simple web app built with express.js. Let's see how large the dependency tree is using ndu:

$ npm install -g ndu
$ ndu --open

This opens your web browser and shows a breakdown of your app's dependency tree:

From here you can see that your app is using 9.64MB of node dependencies. You can highlight areas of the diagram to see which node dependencies use up that space:

This can be especially helpful in a large application. Sometimes just a few dependencies make up the majority of your application's size.

For example, here's a real application that was running at Groupon. You can easily see how one bloated dependency was increasing the size of the application by 10%:

Thanks to ndu, it was easy to clean up the largest dependencies and quickly shrink the size of the app's footprint.

Similar Tools

• disc: For analyzing the size of browserify bundles, platform independent
• space-hogs: Generic directory size info, highlights big entries, *nix
• WinDirStat: Generic directory size info, Windows
• Grand Perspective: Generic directory size info, OSX