Я пытаюсь создать систему входа в систему nodejs, используя Express и Passport, я получаю сообщение об ошибке

Question

Я обновил всю зависимость в моем package.json и установил все необходимые. И я попробовал с YouTube и отредактировал мой файл app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require('express-session');
var passport = require('passport');
var expressValidator = require('express-validator');
var LocalStrategy = require('passport-local').Strategy;
var multer = require('multer');
var upload = multer({dest: './uploads'});
var flash = require('connect-flash');
var mongo = require('mongodb');
var mongoose = require('mongoose');
var db = mongoose.connection;

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

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

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

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

// Passport
app.use(passport.initialize());
app.use(passport.session());

// Validator
app.use(expressValidator({
  errorFormatter: function(param, msg, value) {
      var namespace = param.split('.')
      , root    = namespace.shift()
      , formParam = root;

    while(namespace.length) {
      formParam += '[' + namespace.shift() + ']';
    }
    return {
      param : formParam,
      msg   : msg,
      value : value
    };
  }
}));

app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use(flash());
app.use(function (req, res, next) {
  res.locals.messages = require('express-messages')(req, res);
  next();
});

app.use('/', routes);
app.use('/users', users);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});


module.exports = app;

Но когда я пытаюсь запустить файл, поместив команду запуска npm

Эта ошибка приходит

C:\nodeproject\nodeauth\app.js:45
app.use(expressValidator({
        ^

TypeError: expressValidator is not a function
    at Object.<anonymous> (C:\nodeproject\nodeauth\app.js:45:9)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Module.require (internal/modules/cjs/loader.js:849:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (C:\nodeproject\nodeauth\bin\www:7:11)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! nodeauth@0.0.0 start: `node ./bin/www`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the nodeauth@0.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

Я даже проверил модуль Express Validator, но, похоже, ничего не получается.

Answer 1

See below example
// ...rest of the initial code omitted for simplicity.
const { check, validationResult } = require('express-validator');

app.post('/user', [
  // username must be an email
  check('username').isEmail(),
  // password must be at least 5 chars long
  check('password').isLength({ min: 5 })
], (req, res) => {
  // Finds the validation errors in this request and wraps them in an object with handy functions
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(422).json({ errors: errors.array() });
  }

  User.create({
    username: req.body.username,
    password: req.body.password
  }).then(user => res.json(user));
});