app.js

let createError = require('http-errors');
let express = require('express');
let path = require('path');
let cookieParser = require('cookie-parser');
let logger = require('morgan');
let cors = require('cors');
let indexRouter = require('./routes/index');
let  model = require('./models');
let app = express();
let config = require('./config.js');

//Import the mongoose module
let mongoose = require('mongoose');

//Set up default mongoose connection
let mongoDB = config.dbUrl;

mongoose.connect(mongoDB, { useNewUrlParser: true, useUnifiedTopology: true, useCreateIndex: true, useFindAndModify: false });
mongoose.connection.on("connected",(err,res) => {
    console.log("mongoose is connected");
});


app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use(cors({origin: 'http://localhost:4200'}));
app.use('/api', indexRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};
  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;