npm i passport-jwt jsonwebtoken

// ./config.js
module.exports = {
 secretKey: '12345-67890-9876-54321',
 mongoUrl: 'mongodb://localhost:27017/confusion'
}

var config = require('./config')
...
const url = config.mongoUrl
const connet = mongoose.connect(url, {useNewUrlParse: true, useCreateIndex: true})

./authenticate.js
var passport = require('passport'),
 LocalStrategy = require('passport-local').Strategy,
 User = require('./models/user')

var JwtStrategy = require('passport-jwt').Strategy,
 ExtractJwt = require('passport-jwt').ExtractJwt,
 jwt = require('jsonwebtoken')

var config = require('./config.js')

passport.use(new LocalStrategy(User.authenticate()))
passport.serializeUser(User.serializeUser())
passport.deserializeUser(User.deserializeUser())

exports.getToken = function (user) {
 return jwt.sign(user, config.secretKey, {expiresIn: 3600}) // 签发token时设置超时时间是3600s
}

var opts = {}
opts.jwtFromRequest = ExtractJwt.fromAuthHeaderAsBearerToken() // 从验证头中提取，模型默认是`'bearer'`.
opts.secretOrKey = config.secretKey

exports.jwtPassport = passport.use(new JwtStrategy(opts, (jwt_payload, done) => {
 console.log('JWT payload: ', jwt_payload)
 User.findOne({_id: jwt_payload._id}, (err, user) => {
 if (err) {
 return done(err, false)
 } else {
 if (user) {
 return done(null, user)
 } else {
 return done(null, false)
 }
 }
 })
}))

exports.verifyUser = passport.authenticate('jwt', {session: false}) // 使用jwt就不再需要session保存用户数据了。

// routes/users.js
...
var authenticate = require('../authticate')
router.post('/login', passport.authenticate('local'), (req, res) => { // 登录时还是使用passport-local
 var token = authenticate.getToken({_id: req.user._id}) // 得到签发后的jwt
 res.statusCode = 200
 res.setHeader('Content-Type', 'application/json')
 res.json({success: true, token: token, status: 'You are successful logged in!'})
})

// use localStorage
$.ajax({
 type: 'post',
 dataType: 'json',
 url: 'users/login',
 data: {
 username: 'un',
 password: 'pw'
 },
 success: funciton (res) {
 localStorage.token = getToken(res)
 },
 error: funciton (err) {...}
})
// 还可以使用vux方法。
// 还可以使用封装axios方法。

err = {
 name: 'TokenExpiredError',
 massage: 'jwt expired',
 expired: [ExpDate]
}
JsonWebTokenError

err = {
 name: 'JsonWebTokenError',
 message: 'jwt malformed' // 'jwt malformed', 'jwt signature in required', 'invalid signature', 'jwt audience invalid. expected: [OPTIONS AUDIENCE]', 'jwt issuer invalid. expected: [OPTIONS ISSUER]', 'jwt id invalid. expected:[OPTIONS JWT ID]', 'jwt subject invalid. expected: [OPTIONS SUBJECT]'
}

err = {
 name: 'NotBeforeError',
 message: 'jwt not active',
 date: 2018-10-04T16:10:44.000Z
}

// authenicate.js
...
export.verifyUser = passport.authenticate('jwt', {
 session: false,
 failureRedirect: '/error/auth' // 在这个路由里统一处理验证不通过的事情
 })

// routes/error.js
...
router.get('/auth', (req, res, next) => {
 let header = req.headers
 let rawToken = header.authorization
 if (!rawToken.split(' ').length) {
 res.json({ // 统一的数据结构方便前端使用
 code: 403,
 data: {},
 message: 'error for get token'
 })
 } else {
 let token = rawToken.split(' ')[1]
 jwt.verify(token, config.secretKey, err => { // 这里用到jsonwebtoken/config。注意引用
 switch (err.name) {
 case 'TokenExpiredError':
 case 'NotBeforeError':
  let payload = jwt.decode(token)
  token = authenticate.getToken({_id: payload._id})
  res.statusCode = 200
  res.setHeader('Content-Type', 'application/json')
  res.json({success: true, token: token, status: '已经刷新token'})
  break
 case 'JsonWebTokenError':
 default:
  res.statusCode = 401
  res.json({
  code: 401,
  data: {
  error: err
  },
  message: 'token错误'
  })
  break
 }
 })
 }
 })