In my nodejs app it shows an error like:

req.flash is not a function

I have installed connection-flash npm and session and express-session but instead of that it is throwing an error like:

TypeError: req.flash is not a function

in line no. 42 in my register.js. I googled it several times but did not find any proper solution. How can I solve this? Thanks in advance.

This is my register.js:

var express = require('express');
var router = express.Router();
var User = require('../models/user');
var flash = require('connect-flash');
router.get('/', (req, res, next) => {
    res.render('register');
})


router.post('/', (req, res, next) => {
    var name = req.body.name;
    var username = req.body.username;
    var email = req.body.email;
    var password = req.body.password;
    var cpassword = req.body.cpassword;

    req.checkBody('name', 'Name is required').notEmpty();
    req.checkBody('username', 'User Name is required').notEmpty();
    req.checkBody('email', 'Email is required').notEmpty();
    req.checkBody('email', 'Email is not valid').isEmail();
    req.checkBody('password', 'Password is required').notEmpty();
    req.checkBody('cpassword', 'Password do not match').equals(req.body.password);

    var errors = req.validationErrors();
    if(errors){
        res.render('register', {
            errors:errors
        });
    }else{
        var newUser = new User({
            name: name,
            username: username,
            email: email,
            password: password
        });
        User.createUser(newUser, function(err, user){
            if(err) throw err;
            console.log(user)
        });

        req.flash('success_msg', 'Successfully Registered');
        res.redirect('/login');
    }
})
module.exports = router;

And this is my app.js:

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var expressValidator = require('express-validator');
var passport = require("passport");
var LocalStrategy = require('passport-local').Strategy;

var session = require('session');

var flash = require('connect-flash');
var mongoose = require('mongoose');



var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var loginRouter = require('./routes/login');
var registerRouter = require('./routes/register');

var app = express();

app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'twig');

app.use(expressValidator());

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));


app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/login', loginRouter);
app.use('/register', registerRouter);


app.use(flash());

app.use(function(req, res, next) {
    res.locals.success_msg = req.flash('success_msg');
    res.locals.error_msg = req.flash('error_msg');
    res.locals.error = req.flash('error');
    res.locals.user = req.user || null;
    next();
})

app.use(passport.initialize());
app.use(passport.session());
app.use(function(req, res, next) {
  next(createError(404));
});



app.use(function(err, req, res, next) {
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

In my nodejs app it shows an error like:

req.flash is not a function

I have installed connection-flash npm and session and express-session but instead of that it is throwing an error like:

TypeError: req.flash is not a function

in line no. 42 in my register.js. I googled it several times but did not find any proper solution. How can I solve this? Thanks in advance.

This is my register.js:

var express = require('express');
var router = express.Router();
var User = require('../models/user');
var flash = require('connect-flash');
router.get('/', (req, res, next) => {
    res.render('register');
})


router.post('/', (req, res, next) => {
    var name = req.body.name;
    var username = req.body.username;
    var email = req.body.email;
    var password = req.body.password;
    var cpassword = req.body.cpassword;

    req.checkBody('name', 'Name is required').notEmpty();
    req.checkBody('username', 'User Name is required').notEmpty();
    req.checkBody('email', 'Email is required').notEmpty();
    req.checkBody('email', 'Email is not valid').isEmail();
    req.checkBody('password', 'Password is required').notEmpty();
    req.checkBody('cpassword', 'Password do not match').equals(req.body.password);

    var errors = req.validationErrors();
    if(errors){
        res.render('register', {
            errors:errors
        });
    }else{
        var newUser = new User({
            name: name,
            username: username,
            email: email,
            password: password
        });
        User.createUser(newUser, function(err, user){
            if(err) throw err;
            console.log(user)
        });

        req.flash('success_msg', 'Successfully Registered');
        res.redirect('/login');
    }
})
module.exports = router;

And this is my app.js:

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var expressValidator = require('express-validator');
var passport = require("passport");
var LocalStrategy = require('passport-local').Strategy;

var session = require('session');

var flash = require('connect-flash');
var mongoose = require('mongoose');



var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var loginRouter = require('./routes/login');
var registerRouter = require('./routes/register');

var app = express();

app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'twig');

app.use(expressValidator());

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));


app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/login', loginRouter);
app.use('/register', registerRouter);


app.use(flash());

app.use(function(req, res, next) {
    res.locals.success_msg = req.flash('success_msg');
    res.locals.error_msg = req.flash('error_msg');
    res.locals.error = req.flash('error');
    res.locals.user = req.user || null;
    next();
})

app.use(passport.initialize());
app.use(passport.session());
app.use(function(req, res, next) {
  next(createError(404));
});



app.use(function(err, req, res, next) {
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

• javascript
• node.js

4 Answers 4

Do you try move app.use(flash()) before app.use('/register... ?

app.use(flash());

app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/login', loginRouter);
app.use('/register', registerRouter);

and base of flash-connection documnet

Flash messages are stored in the session. First, setup sessions as usual by enabling cookieParser and session middleware. Then, use flash middleware provided by connect-flash.

Follow the document instruction to use flash properly

Use express-flash instead:

1. npm install express-flash --save

2. In app.js file add

   flash = require('express-flash')
   app.use(
       session({
         resave: true,
         saveUninitialized: true,
         secret:"yash is a super star",
         cookie: { secure: false, maxAge: 14400000 },
       })
   );
   app.use(flash());
   

3. use req.flash function wherever you want to send flash messages

   res.flash("info","this message will be displayed");
   res.redirect('');
   

4. In index.hbs file include

   {{#if messages.info}}
   {{messages.info}}
   {{if}}
   

1. Define session first.

   app.use(
     session({
       secret: 'secret',
       resave: true,
       saveUninitialized: true
     })
   );
   

2. Then Define flash

   app.use(flash());
   

3. Then define your router

   app.use('/', indexRouter);
   app.use('/users', usersRouter);
   

The way how you arranged your middlewares are wrong. If you want to use the flash middileware in your route files, then the flash middileware should be above your router middileware. Like this:

app.use(flash());
app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/login', loginRouter);
app.use('/register', registerRouter);