Ok I've downloaded some of the compromised packages and you can search your already downloaded node modules for possibly infected packages using this command:
find ./node_modules -type f -name "bun_environment.js"
You can check your user level node cache using:
find ~/.npm -type f -name "bun_environment.js"
Still sizing this one up but if you get any hits check and see if they are big files (around 10MB) and if so you're likely infected.