Fix 'Cannot find package mem-fs' Import Error

When Node.js cannot locate the mem‑fs package, it usually means the dependency is missing, incorrectly installed, or incompatible with your project setup. Here are the most reliable ways to fix it.

1. Install the Package (Local Install Recommended)

npm install mem-fs --save
# or
yarn add mem-fs

Avoid global installs unless required:

npm install -g mem-fs   # not recommended

2. Check package.json

{
  "dependencies": {
    "mem-fs": "^1.0.0"
  }
}

If missing → reinstall.

3. Clear Cache & Reinstall Dependencies

npm cache clean --force
rm -rf node_modules
npm install

Yarn:

yarn cache clean
rm -rf node_modules
yarn install

4. Fix Import / Require Mismatch

CommonJS:

const memFs = require('mem-fs');

ESM:

import memFs from 'mem-fs';

❗ Mismatched module systems often cause this error.

5. Verify Node.js Compatibility

node -v
npm -v

6. Install a Compatible Version

npm install mem-fs@1.1.3

7. Local vs Global Conflict

If installed globally but not locally:

npm link mem-fs

Recommendation: always install locally.

8. Using mem‑fs with Yeoman? Use This Template

const memFs = require('mem-fs');
const editor = require('mem-fs-editor');

const store = memFs.create();
const fs = editor.create(store);

Summary

Conclusion

The error is almost always caused by a missing install, module mismatch, or corrupted node_modules. Follow the steps above to resolve it quickly.