Multiple local strategies with passport

app.js

let User = require('./models/userModel')
passport.use(User.createStrategy());

let Enterprise = require('./models/enterpriseModel')
let EnterpriseStrategy = require('passport-local').Strategy
passport.use('enterprise-local', new EnterpriseStrategy(Enterprise.authenticate()))

passport.serializeUser(function(user, done) {
  let type
  if (isUser(user)) {
    type = 'user'
  } else if (isEnterprise(user)) {
    type = 'enterprise'
  }
  
  const key = {
    id: user.id,
    // With ES6 we don't need to put 'type: type'
    type
  }
  
  done(null, key)
});


passport.deserializeUser(function(key, done) {
  // Check if user should be searched in the User model or
  // in the Enterprise one
  const Model = key.type === 'user' ? User : Enterprise
  // Find the user, if found then pass it to the done() function
  Model.findOne({
    _id: key.id
  }, '-salt -password', function(err, user) {
    done(err, user);
  }
}

// Checks if the user is an instance of the User model
const isUser = user => user instanceof User

// Checks if the user is an instance of the Enterprise model
const isEnterprise = user => user instanceof Enterprise