Detecting Changes in `node_modules` for Patch Package

When you edit files inside node_modules, Git does not track them --- so git status won't help detect changes.
This guide explains how to use sha1sum (or md5sum) to detect modified packages.

🧰 Check Compatibility

Ensure that sha1sum is available in your system (run this in bash, not PowerShell):

$ sha1sum --help
Usage: sha1sum [OPTION]... [FILE]...
Print or check SHA1 (160-bit) checksums.

If you see similar output, the command is ready to use.

🔍 Generate Hash for `node_modules`

1. Generate hash for all `.js` files

find node_modules -type f -name "*.js" | sort | xargs sha1sum > .node_modules.hash

2. Generate hash for all files

find node_modules -type f | sort | xargs sha1sum > .node_modules.hash

3. Skip large/binary files

To skip .png, .jpg, .jar, and .aar files:

find node_modules -type f ! -name "*.png" ! -name "*.jpg" ! -name "*.jar" ! -name "*.aar" | sort | xargs sha1sum > .node_modules.hash

4. Faster hash using `md5sum`

find node_modules -type f -name "*.js" | sort | xargs md5sum > .node_modules.hash

📄 Example of Generated `.node_modules.hash`

Each line includes the hash and file path:

116d3be5fc68bb1840a26330c47bd986508c7e5b *node_modules/@twotalltotems/react-native-otp-input/index.js

🧪 Detect Changed Files

After editing and saving files inside node_modules, run:

sha1sum -c .node_modules.hash | grep FAILED | awk -F'[:/]' '{print $1} {print $2} {print $3}' | sort -u

Example output:

sha1sum: WARNING: 1 computed checksum did NOT match
@twotalltotems
node_modules
react-native-otp-input

This output indicates which package(s) need to be patched.

🧩 Create Patch with Yarn

Once you've identified the modified package, create a patch using:

yarn patch-package

✅ Done!
You can now track which packages have been manually edited and safely generate patch files.

4sskick/check-node-modules-diff.md

Detecting Changes in node_modules for Patch Package