How to find out which NPM packages a live Node.js app is using?

Other Questions NPM
1

I’m working on a Node.js project and I’m curious about something. Is there a way to see what NPM packages my app is using while it’s running? I know I can look at the package.json file, but I’m wondering if there’s another method. Maybe Node keeps this info somewhere I can access?

Here’s a simple example of what I mean:

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(3000, () => {
  console.log('Server running on port 3000');
});

// How can I get a list of dependencies here?

Does anyone know if there’s a way to get this info from inside the running app? Thanks for any help!

2

yo, have u checked out the ‘process.modules’ object? it’s pretty handy for this kinda stuff. just do a console.log(Object.keys(process.modules)) in ur running app and it’ll show u all the loaded modules. not perfect, but it gives u a good idea of whats going on under the hood.

3

While the other responses offer some good insights, there’s another approach worth considering. You can use the ‘npm list’ command in your terminal to see a tree of all installed packages, including their dependencies. For a running application, you might consider implementing a route or endpoint that executes this command and returns the result.

Here’s a basic example:

const { exec } = require('child_process');

app.get('/packages', (req, res) => {
  exec('npm list --json', (error, stdout, stderr) => {
    if (error) {
      res.status(500).send(error);
      return;
    }
    res.send(JSON.parse(stdout));
  });
});

This method provides a comprehensive view of your dependencies, including nested ones, which can be quite useful for debugging or auditing purposes.

4

I’ve actually faced this exact situation before! In my experience, there are a couple of ways to approach this. One method I’ve found particularly useful is using the process.mainModule.children array. This gives you access to all the loaded modules.

Here’s a quick snippet I’ve used in the past:

const modules = process.mainModule.children.map(child => child.filename);
console.log(modules);

This will log out the filenames of all loaded modules. It’s not perfect, as it doesn’t directly map to npm package names, but it’s a good starting point.

Another approach I’ve used is the require.cache object. It contains references to all loaded modules. You can iterate over it like this:

Object.keys(require.cache).forEach(key => {
  console.log(key);
});

These methods aren’t foolproof, but they’ve helped me debug and understand my running applications better. Hope this helps!