Simple Mongoose Authentication

const express = require('express')
const app = express()
const bcrypt = require('bcrypt')
const mongoose = require('mongoose')

var bodyParser = require('body-parser')
app.use(bodyParser.json())


mongoose.connect('mongodb://localhost/my_database', {
  useNewUrlParser: true,
  useUnifiedTopology: true
});


const Schema = mongoose.Schema;
const ObjectId = Schema.ObjectId;

const UserSchema = new Schema({
  id: ObjectId,
  name: {type:String,required: true,unique: true},
  password: {type:String,required: true},
  email: {type:String,required: true,unique: true},
});
var User = mongoose.model('User', UserSchema);





const users = []

app.get('/users', (req, res) => {
  res.json(users)
})


app.post('/users', async (req, res, next) => {

  const check = await User.find({ email: req.body.email })
  if (check.length == 0) {
    try {
      const hashedpw = await bcrypt.hash(req.body.password, 10)
      const user = { name: req.body.name, password: hashedpw, email: req.body.email }
      User.create(user, (err, user) => {
        if (err) {
          return next(err.message)
        } else {
          res.status(201).send(users)
        }
      })
    } catch (e) {
      res.status(500).send(e)

    }
  } else {
    res.status(200).send("User already Exist")

  }
})



app.post('/users/login', async (req, res) => {

  const user = await User.find({name:req.body.name})
  if(user.length == 0 ){
    return res.status(400).send('cannot find user')
  } 
  
  try {
    if (await bcrypt.compare(req.body.password, user[0].password)) {
      res.status(201).send(user[0])

    } else {
      res.status(201).send("not allowed")

    }
  } catch (e) {
    res.status(500).send("failed")
  }

})

app.listen(3000)