login.js

  const bcrypt = require('bcrypt')
    const jsonwebtoken = require('jsonwebtoken')

    app.post('/login', (req, res) => {
      const user = await User.findOne({ where: { req.body.email } })

      if (!user) {
        throw new Error('No user with that email')
      }

      const valid = await bcrypt.compare(req.body.password, user.password)

      if (!valid) {
        throw new Error('Incorrect password')
      }

      // signin user and generate a jwt
      const token = jsonwebtoken.sign({
        id: user.id,
        email: user.email
      }, 'somesuperdupersecret', { expiresIn: '1y' })

      // return json web token
      res.json({
        message: 'Authentication successful!',
        data: token
      })
    })