Problem: You want to find copy/pasted code
Problem: You want to find copy/pasted code.
Solution: jscpd.
It finds copy/pasted code in over 150 languages. I just ran this command on a JS project:
npx jscpd --ignore "**/node_modules/**"
It found over 6,000+ lines of duplicated code.
Note: The node_modules glob I used above uses a leading ** due to a bug: https://github.com/kucherenko/jscpd/issues/611