Fatal: unable to get current working directory: Operation not permitted

New to Node.js and JavaScript (my environment is currently set-up for RoR); I run into the following error described in the title when trying to test code by installing project dependencies npm i (listed here: https://www.npmjs.com/package/doubleratchet). I think at some point I need to do run node index.js but am unsure. When I look up node -v command is not found.

For additional reference and context, the code I am trying to test for functionality is here, which is a JavaScript executable script on the command line: https://github.com/Itp-test/double-ratchet-test

Essentially, I'm trying to check if the 1) Send (arguments: message to send) 2) Receive (arguments: the encrypted message) 3) Also, arguments are whether you're person 1 or 2, then sending will output the encrypted message and receiving outputs the decrypted message

If anyone can help point me in the right direction as to how I can go about testing this command line script that would be greatly appreciated. Thank you.