// import mongoose and connect to mongoDB
const mongoose = require('mongoose')
mongoose.connect('mongodb://localhost/restaurant', { useNewUrlParser: true })
const db = mongoose.connection

// actions if connect error
db.on('err', (err) => {
  if (err) return console.error(err)
})

// actions if connect success
db.once('open', (err) => {
  if (err) return console.error(err)
  console.log('connect to mongoDB successifully !')
})