Implement login registration function code (Node.js+Express+MongoDB)

var mongoose = require("mongoose");

var bodyParser = require("body-parser"); 
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

var cookieParser = require('cookie-parser');
var session = require('express-session');
ar mongoStore = require('connect-mongo')(session);
var dbUrl = 'mongodb://localhost/express';
app.use(cookieParser()); 
app.use(session({
 secret:'express',
 store: new mongoStore({
 url: dbUrl,
 collection: 'sessions'
 })
}));

doctype html
html
 head
  meta(charset='utf-8')
  title #{title}
  include ./includes/head
 body
  include ./includes/header
  block content

link(href='css/main.css', rel='stylesheet')
link(href="/libs/bootstrap/dist/css/bootstrap.min.css" rel="external nofollow" , rel="stylesheet")
script(src="/libs/jquery/dist/jquery.min.js")
script(src="/libs/bootstrap/dist/js/bootstrap.min.js")

.container
 .row
  .page-header
   h1 #{title}
.navbar.navbar-default.navbar-fixed-bottom
 .container
  if user
   p.navbar-text.navbar-right
    span 欢迎你,#{user.name}
    span  | 
    a.navbar-link(href="/layout" rel="external nofollow" ) 退出登录
  else
   p.navbar-text.navbar-right
    a.navbar-link(href="/signup" rel="external nofollow" , data-toggle="modal", data-target="#signupModal") 注册
    span  | 
    a.navbar-link(href="/login" rel="external nofollow" , data-toggle="modal", data-target="#signinModal") 登录

include ../layout
 block content
  form.form-horizontal( role="form", method="POST", action='/user/signup')
   .form-group
    label.col-sm-2.control-label(for="signupName") 用户名
    .col-sm-10
     input#signupName.form-control(type="text", name="user[name]", placeholder="输入用户名")
   .form-group
    label.col-sm-2.control-label(for="signuppassword") 密码
    .col-sm-10
     input#signuppassword.form-control(type="password", name="user[password]", placeholder="输入密码")
   .form-group
    label.col-sm-2.control-label(for="signupemail") 邮箱
    .col-sm-10
     input#signupemail.form-control(type="email", name="user[email]", placeholder="输入邮箱")
   .form-group
    .col-sm-offset-2.col-sm-10
     button.btn.btn-default(type="submit") 完成注册

// 注册页面
app.get('/signup', function (req,res) {
 res.render('signup', {
 title: '注册'
 });
});
// 登录页面
app.get('/login', function (req,res) {
 res.render('login', {
 title: '登录'
 });
});

// 注册表单
app.post('/user/signup', function (req,res) {
 var _user = req.body.user;
 User.findOne({name:_user.name}, function (err, user) {
 if(err){
  console.log(err);
 }
 if(user) {
  return res.redirect('/login');
 } else {
  var user = new User(_user);
  user.save(function (err, user) {
  if(err){
   console.log(err);
   res.redirect('/signup');
  }
  console.log('注册成功——用户名:' + user);
  res.redirect('/login'); 
  });
 }
 });
});

// 登录表单
app.post('/user/login', function (req,res) {
 var _user = req.body.user;
 var name = _user.name;
 var password = _user.password;
 User.findOne({name:name}, function (err, user) {
 if(err){
  console.log(err);
 }
 if(!user) {
  return res.redirect('/signup');
 }
 user.comparePassword(password, function (err, isMatch) {
  if (err){
  console.log(err);
  }
  if (isMatch) {
  req.session.user = user; // 用户名存入session中
  console.log('登录成功——用户名: ' + user);
  return res.redirect('/');
  } else {
  return res.redirect('/lgoin');
  }
 });
 });
});

app.get('/layout', function(req,res){
 delete req.session.user;
 //delete app.locals.user; // 删除全局变量user,否则点击退出登录,页面无变化
 res.redirect('/');
});

mongoose.connect("mongodb://localhost/express"); // 连接数据库

//schemas/user.js
var mongoose = require('mongoose');
var bcrypt = require('bcrypt');
var SALT_WORK_FSCTOR = 10; // 计算强度,越大破解越困难
var UserSchema = new mongoose.Schema({
 name: {
 unique: true,
 type:String
 },
 password: String,
 email:String,
 meta: {
 createAt: {
  type: Date,
  default: Date.now()
 },
 updateAt: {
  type: Date,
  default: Date.now()
 }
 }
});
//每次存入数据时都进行判断
UserSchema.pre('save', function (next) {
 var user = this;
 if (this.isNew) { // 数据是新数据
 this.meta.createAt = this.meta.updateAt = Date.now();
 } else {
 this.meta.updateAt = Date.now();
 }
 //密码 加盐
 bcrypt.genSalt(SALT_WORK_FSCTOR, function (err, salt) {
 if (err) {
  return next(err);
 }
 bcrypt.hash(user.password, salt, function (err, hash) {
  if (err) {
  return next(err);
  }
  user.password = hash;
  next();
 });
 });
});
UserSchema.methods = {
 comparePassword: function (_password, cb) {
 bcrypt.compare(_password, this.password, function (err, isMatch) {
  if (err) {
  return cb(err);
  }
  cb(null, isMatch);
 })
 }
};
UserSchema.statics = {
 fetch: function (cb) {
 return this
  .find({})
  .sort('meta.updateAt')
  .exec(cb);
 },
 findById: function (id, cb) {
 return this
  .findOne({_id: id})
  .exec(cb)
 }
};

module.exports = UserSchema;

// models/user.js
var mongoose = require('mongoose');
//模式
var UserSchema = require('../schemas/user');
//编译模型
var User = mongoose.model('user',UserSchema);
module.exports = User;

//app.js
var User = require('./models/user');
app.set('view engine', 'jade'); // jade模板引擎
app.set("views", "./views/pages/"); // 视图根目录
var serveStatic = require('serve-static'); // 静态文件处理
app.use(serveStatic('public')); // 路径：public

app.use(function (req, res, next) {
 var _user = req.session.user;
 app.locals.user = _user;
 return next();
});