我正在使用express模板引擎学习node.js，我正在按照udemy课程“通过构建10个项目学习Node.js”的教学视频进行学习，在跟随一节课时，当教授运行
我已经尝试过比对代码，但是它们是相同的。请帮助我解决这个错误，我被卡在这里已经几小时了，尝试了很多修改，但对我来说都没有起作用。
npm start localhost:3000 时，教授的程序可以启动，但我的出现了错误，指出app.use需要中间件函数。我已经尝试过比对代码，但是它们是相同的。请帮助我解决这个错误，我被卡在这里已经几小时了，尝试了很多修改，但对我来说都没有起作用。
当我尝试运行 'npm start' 时，会弹出以下错误：
TypeError：app.use()需要中间件函数
以下是app.js的代码：
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var expressValidator = require('express-validator');
var cookieParser = require('cookie-parser');
var session = require('express-session');
var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var bodyParser = require('body-parser');
var multer = require('multer');
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');
//Handle File Uploads
app.use(multer({
dest: './uploads'
}));
// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: false
}));
//Handle Express Sessions
app.use(session({
secret: 'secret',
saveUninitialied: 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;
这是 package.json 文件
{
"name": "nodeauth",
"version": "1.0.0",
"private": true,
"scripts": {
"start": "node ./bin/www"
},
"dependencies": {
"body-parser": "~1.12.4",
"cookie-parser": "~1.3.5",
"debug": "~2.2.0",
"express": "~4.12.4",
"jade": "~1.9.2",
"morgan": "~1.5.3",
"serve-favicon": "~2.2.1",
"mongodb": "*",
"mongoose": "*",
"connect-flash": "*",
"express-validator": "*",
"express-session": "*",
"express-messages": "*",
"passport": "*",
"passport-local": "*",
"passport-http": "*",
"multer": "*"
}
}
这是更新后的app.js文件（移除multar后）
var express = require('express'),
path = require('path'),
favicon = require('serve-favicon'),
logger = require('morgan'),
cookieParser = require('cookie-parser'),
expressValidator = require('express-validator'),
session = require('express-session'),
passport = require('passport'),
LocalStrategy = require('passport-local').Strategy,
bodyParser = require('body-parser'),
flash = require('connect-flash'),
mongo = require('mongodb'),
mongoose = require('mongoose'),
db = mongoose.connection,
routes = require('./routes/index'),
users = require('./routes/users'),
app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
// handle file uploads
//multer delted
// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
// handle express sessions
app.use(session({
secret: 'keyboard cat',
resave: true,
saveUninitialized: 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')));
// flash
app.use(flash());
// express messages
app.use(function(req, res, next) {
res.locals.messages = require('express-messages')(req, res);
next();
});
app.get('*', function(req, res, next) {
res.locals.user = req.user || null;
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: {}
});
});
//Express server
var http = require('http');
var server = http.createServer(app);
app.get('/', function(req, res) {
res.send("Hello World!");
});
server.listen(3000, 'localhost');
server.on('listening', function() {
console.log('Express server started on port %s at %s', server.address().port, server.address().address);
});
module.exports = app;