express nodejs Passportjs 总是失败Rederict

Question

首先，我尝试了文档中的代码： http://www.passportjs.org/docs/username-password/ TypeError: req.flash is not a ZC1C425268E68385D1AB5074C17A4

在尝试了文档中的示例代码后，我尝试了 Github 页面上发布的代码：

 var passport = require('passport')
  , LocalStrategy = require('passport-local').Strategy;

  var flash=require("connect-flash");
  const express = require('express')
const app = express()
const port = 4000


app.use(flash());
app.use(require('cookie-parser')());
app.use(require('body-parser').urlencoded({ extended: true }));
app.use(require('express-session')({ secret: 'keyboard cat', resave: true, saveUninitialized: true }));
app.use(passport.initialize());


passport.use(new LocalStrategy({ passReqToCallback : true},
    function(username, password, done) {
      User.findOne({ username: username }, function(err, user) {
        if (err) { return done(err); }
        if (!user) {
          return done(null, false, { message: 'Incorrect username.' });
        }
        if (!user.validPassword(password)) {
          return done(null, false, { message: 'Incorrect password.' });
        }
        return done(null, user);
      });
    }
  ));


  app.post('/login', 
  passport.authenticate('local', { failureRedirect: '/login2' }),
  function(req, res) {
    res.redirect('/yes');
  });




app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening at http://localhost:${port}`)
})

在 Insomie 中，我在执行 POST 请求时得到以下结果，这表明执行了 failureRedirect。