If it is a library based only on javascript, than you can just run npm uninstall --save package_name or npm uninstall --save-dev package_name
If you've installed a library with native content that requires linking, and you've linked it with npm then you can do: npm unlink package_name then follow step 1
If you've installed a library with native content manually, then just undo all the steps you took to add the library in the first place. Then follow step 1.