Error: Cannot find module './keys_dev' Require stack

Question

I have cloned a GitHub repo for reference. But i don't know what this.keys_dev refers to. Everything seems fine to me. But it is returning me error. Everything is in its place as expected. I hope anyone can help me. It requires stack that is unknown to me. It is requiring api that is already defined. I need to understand can anyone help?

const express = require("express");
const bodyPaser = require('body-parser');
const mongoose = require('mongoose');
const passport = require('passport');
const path = require('path');
const cors = require('cors');

const users = require('./routes/api/users');
const level = require('./routes/api/levels');
const employee = require('./routes/api/employees');
const exception = require('./routes/api/exception');
const payslip = require('./routes/api/payslip');
const dashboard = require('./routes/api/dashboard');
const individualcost = require('./routes/api/individualcost');
const oneoffpayment = require('./routes/api/oneoffpayment');
const record = require('./routes/api/record');

const app = express();

//Body parser middleware
app.use(bodyPaser.urlencoded({ extended: false }));
app.use(bodyPaser.json());
app.use(cors())

//Db
const db = require("./config/keys").mongoURI;

//MongoDB connection
mongoose
  .connect(
    db,
    { useNewUrlParser: true }
  )
  .then(() => console.log("MongoDB connected"))
  .catch(err => console.log(err));

//Passport Middleware
app.use(passport.initialize());

//Passport config
require('./config/passport')(passport);


//Use routes
app.use('/api/users', users);
app.use('/api/level', level);
app.use('/api/employee', employee);
app.use('/api/exception', exception);
app.use('/api/payslip', payslip);
app.use('/api/dashboard', dashboard);
app.use('/api/individualcost', individualcost);
app.use('/api/oneoffpayment', oneoffpayment);
app.use('/api/record', record);

// Server static assets if in production
if (process.env.NODE_ENV === 'production') {
  // Set static folder
  app.use(express.static('client/build'));

  app.get('*', (req, res) => {
    res.sendFile(path.resolve(__dirname, 'client', 'build', 'index.html'));
  });
}

const PORT = process.env.PORT || 5000;
app.listen(PORT, () => console.log(`App is running on port ${PORT}`));

Answer 1

const db = require("./config/keys").mongoURI;

This require is fetching application configurations from the local filesystem, in this case the db URI. Perhaps the author of the repo forgot to mention that detail? It's very likely that if you want to use a MongoDB you'll have to setup your own local or cloud database and create a file under config/keys that contains a mongoURI. This should look similar to this:

// this is the contents of ./config/keys
export default {
  mongoURI: "mongodb+srv://project:your-mongo-uri-here",
};

If you're looking to start a mongo cluster on the cloud, I've been using cloud.mongodb for a small pet project, works like a charm and it has a free plan tier.

You can also run mongo locally and just point the mongoURI to your local mongo instance.