Authentication with Node.js, Express, Sequelize, JWT and webtokens

passport.js

const {
  github
} = require('./secrets')
const passport = require('passport')
const gitHubStrategy = require('passport-github2').Strategy
const LocalStrategy = require('passport-local').Strategy
const passportJWT = require('passport-jwt')
const ExtractJWT = passportJWT.ExtractJwt
const JWTStrategy = passportJWT.Strategy
const jwt = require('jsonwebtoken')

const userExist = require('../modules/users').userExists
const userBuild = require('../modules/users').userBuilds
const userUpdate = require('../modules/users').userUpdate

passport.serializeUser((user, done) => {
  done(null, user)
})

passport.deserializeUser((user, done) => {
  userExist(user).then(user => {
    done(null, user)
  })
})

passport.use(
  new gitHubStrategy(
    {
      clientID: github.id,
      clientSecret: github.secret,
      callbackURL: oauthCallbacks.githubCallbackUrl,
      scope: ['user:email']
    },
    (accessToken, accessTokenSecret, profile, done) => {
      process.nextTick(() => {
        const data = {
          provider: profile.provider
          email: profile.emails[0].value
        }

        if (!data.email) {
          return done(null)
        }
        
        userExist(data).then(user => {
          const token = jwt.sign(
            { email: data.email },
            process.env.SECRET_PHRASE
          )
          data.token = token
          return done(null, data)
        })
      })
    }
  )
)

passport.use(
  new LocalStrategy(
    {
      usernameField: 'email',
      passwordField: 'password'
    },
    (email, password, done) => {
      process.nextTick(_ => {
        const userAttributes = {
          email: email
        }
        userExist(userAttributes)
          .then(user => {
            if (!user) return done(null, false)
            if (user.verifyPassword(password, user.password)) {
              const token = jwt.sign(
                { email: user.email },
                process.env.SECRET_PHRASE
              )
              user.token = token
              return done(null, user)
            }
            return done(null, false)
          })
          .catch(error => {
            return done(error)
          })
      })
    }
  )
)

passport.use(new JWTStrategy({
  jwtFromRequest: ExtractJWT.fromAuthHeaderAsBearerToken(),
  secretOrKey: process.env.SECRET_PHRASE
},
(jwtPayload, done) => {
  process.nextTick(_ => {
    const userAttributes = {
      email: jwtPayload.email
    }
    userExist(userAttributes)
      .then(user => {
        if (!user) return done(null, false)
        return done(null, user)
      })
      .catch(error => {
        return done(error)
      })
  })
}
))

why did you use process.nextTick?

@slidenerd I think with nextTick we forward the request so it can be used for other middlewares/routes in other parts of the code which adds logic to this route.