jvzoo-signature-verifier is a nodejs library for dealing with jvzoo ipn signature verification. It's a port of sample code deployed at here.
Use the package manager npm to install jvzoo-ipn-signature-verifier.
npm i jvzoo-ipn-signature-verifier
const JvzooVerifier = require('jvzoo-ipn-signature-verifier');
const verifier = new JvzooVerifier('Your key');
verifier.verify(req.body); # returns 'true' or 'false'
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.