Javascript typeerror:app.use（）需要中间件函数

我正在使用express template engine学习node.js，我正在学习我的课程“通过构建10个项目来学习node.js”，而在教授运行

npm start localhost:3000

启动时，我正在听讲座，而我的则会弹出错误提示app.use需要中间件功能 我尝试过匹配代码和它相同的。请帮助我解决这个错误，我已经在这里停留了几个小时，尝试了很多编辑，但它对我不起作用

当我尝试运行“npm启动”时，会弹出以下错误

TypeError:app.use（）需要中间件函数

下面是app.js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;

这里是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": "*"
  }
}

以下是更新后的app.js（删除multar后）

谢谢您更改：

//Handle File Uploads
app.use(multer({
  dest: './uploads'
}));

例如：

app.use(multer({dest:'./uploads/'}).single('singleInputFileName'));

<form action="/postPhotos" enctype="multipart/form-data">
    <input type="file" name="singleInputFileName">
    <input type="submit" value="Upload photo">
</form>

或

并且要意识到：

app.use(multer({dest:'./uploads/'}).single('singleInputFileName'));

<form action="/postPhotos" enctype="multipart/form-data">
    <input type="file" name="singleInputFileName">
    <input type="submit" value="Upload photo">
</form>

对于第一种情况，或：

<form action="/postPhotos" enctype="multipart/form-data">
    <input type="file" name="multiInputFileName" multiple>
    <input type="submit" value="Upload photo">
</form>

---

对于第二个，在你的html中。

我也在做这门课程&遇到了同样的问题。我按照github中的Multer使用说明解决了此错误：

以下是自述文件中的代码：

    var multer  = require('multer')
    var upload = multer({ dest: 'uploads/' })

&以下是我在编写该教程时用来克服错误的代码：

    var multer = require('multer');
    var upload = multer({ dest: './uploads' });

希望有帮助：）

它是这样工作的。删除这一行

app.use(multer({ dest: './uploads' }));

并将其用作

var multer = require('multer');
var upload = multer({ dest: './uploads' });

我也在走同样的路

这对我来说很有用：

{
  "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": "*"
  }
}

app.use(multer({
  dest: path.join(__dirname, 'public/upload/temp')
}).any());

只换这一行

app.use(multer({dest:'./uploads'}));

到

您可以简单地使用：

app.set(multer({dest: "./uploads"}));

它也适用于我。

替换

app.use（multer（{dest:'./uploads'}））；

到

---

为我工作。

您需要详细添加错误！我无法添加需要10分的图像：（@Tushar:Sir这是错误截图的链接：调试错误的第一步是找到错误发生的那一行。哪一行是/lib/application.js的206行？那是express lib文件，代码没有被我修改，我已经删除了multer，但现在让我再次添加，我真的很抱歉，我失去了访问这个新google帐户的权限。）arlier，不知何故现在可以访问了，谢谢你的帮助：）我的答案比这更年轻、更广泛，为什么不改为检查它呢？Node应该显示一条更具描述性的错误消息我真的很抱歉，但我早些时候失去了对这个新google帐户的访问权限，不知何故现在可以访问了，谢谢你的帮助：）

var upload = multer({dest:'./uploads'});