Welcome to MyRepo. This repository will help you to implement Salesforce OAuth2 with your NodeJS application. This repo uses JSForce, Express library for authentication. Here I have provided the code to call your APEX web service controller into the Node and fetch data from your Salesforce object. Thanks to my brother for his support in implementing this code.
To implement this code you have to change the Client secret and Client consumer key in the app.js file. If you're using Heroku then you can put these credentials into your Heroku App Config Variables.
If you have any error then please let me know.