Express Js/Node Js res.render in controller throwing error

Question

I created a controller file to process the form data and i am replacing the callback function in the routes file with the controller. But res.render in the controller file throws an error anytime i run my node js project. Below is the error i am getting

/

usr/bin/node /home/jebo/Documents/node_projects/cvbuilder/bin/www
/home/jebo/Documents/node_projects/cvbuilder/controllers/register.js:4
        render('user/register',
        ^

TypeError: render is not a function
    at Object.exports.displayRegister (/home/jebo/Documents/node_projects/cvbuilder/controllers/register.js:4:9)
    at Object.<anonymous> (/home/jebo/Documents/node_projects/cvbuilder/routes/user.js:21:44)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Module.require (module.js:596:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/home/jebo/Documents/node_projects/cvbuilder/app.js:13:20)

Process finished with exit code 1

my register controller file

exports.displayRegister = (req, res) => {
        res.render('user/register',
            {
                title: 'Register'
            }
        );
};

exports.postregister = function (req, res, next) {
    body('name').isLength({min: 1}).trim().withMessage('Name empty.')
        .isAlpha().withMessage('Name must be alphabet letters.')

    let user = {
        id: uid.time(),
        fullname: req.body.fullname,
        gender: req.body.gender,
        dob: req.body.dob,
        city: req.body.city,
        country: req.body.country,
        email: req.body.email,
        mobile: req.body.mobile
    }

    let sql = "INSERT INTO user_info SET ?";
    connection.query(sql, user, function(err, rows){
        if(err){
            //show errors on page
            console.log("Error" + err)

            //render register page
            res.render(
                'user/register',
                {
                    message: 'successful'
                }
            )

        }else{
            console.log("Successful" + rows)
            res.redirect('/');
            console.log(user.uid);
        }
    });
}

my route file

const express = require('express');
const router = express.Router();
const { body,validationResult,sanitizeBody  } = require('express-validator');
const connection  = require('../lib/db');
const flash = require('express-flash');
const bodyParser = require('body-parser');
const uid = require('uniqid');
const registercontroller = require('../controllers/register');

/* GET home page. */
router.get('/', function(req, res, next) {
  res.render(
      'user/index',
      {
        title: 'Home'
      }
  );
});

// GET register page
router.get('/register', registercontroller.displayRegister());

//Register User
router.post('/register', registercontroller.postregister());


module.exports = router;

my app.js file

const createError = require('http-errors');
const express = require('express');
const path = require('path');
const cookieParser = require('cookie-parser');
const logger = require('morgan');
const { check, validationResult } = require('express-validator');
const flash = require('express-flash');
const session = require('express-session');
const bodyParser = require('body-parser');
const  mysql = require('mysql');
const connection = require('./lib/db.js');
const indexRouter = require('./routes/index');
const userRouter = require('./routes/user');
const employerRouter = require('./routes/employer');
const adminRouter = require('./routes/admin');

const app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

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('/user', userRouter);
//app.use('/employer', employerRouter);
//app.use('/admin', adminRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

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

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

module.exports = app;

Answer 1

You are registering your routes incorrectly, calling the functions (and thereby passing their return value) instead of just passing the function itself.

Try this instead:

// GET register page
router.get('/register', registercontroller.displayRegister);

//Register User
router.post('/register', registercontroller.postregister);