NodeJS - Express4.0错误：Cannot read property 'Store' of undefined

Express在使用mongodb的时候app配置出错

//settings.js

module.exports={

cookieSecret:"xxxx",

db:"dbname",

host:"localhost",

}

//app.js

var express = require("express");

var settings = require("./settings");

载入connect-mongo的出错写法：

var MongoStore=require("connect-mongo")(express);

app.use(express.session({

    secret:Settings.cookieSecret,

    key:Settings.db,

    cookie:{maxAge:1000*60*60*24*30},//30 days

    store:new MongoStore({

        db:Settings.db

    })

}));

启动后报错：TypeError: Cannot read property 'Store' of undefined

以上是 express<4的写法

express 4.0之后（包含4.0）写法例如以下：

var session = require("express-session");

var MongoStore=require("connect-mongo")(session);

app.use(session({

secret:settings.cookieSecret,

store:new MongoStore({

db:settings.db

})

});

package.json配置例如以下

{

  "name": "dbTest",

  "version": "0.0.1",

  "private": true,

  "scripts": {

    "start": "node ./bin/www"

  },

  "dependencies": {

    "express": "~4.2.0",

    "static-favicon": "~1.0.0",

    "morgan": "~1.0.0",

    "cookie-parser": "~1.0.1",

    "body-parser": "~1.0.0",

    "debug": "~0.7.4",

    "ejs": "~0.8.5",

    "mongodb":"*",

    "connect-mongo":"*",

    "express-session":"*"

  }

}

//假设文件夹下没有运行过npm install请在添加mongodb,connect-mongo,express-session之后在package.json文件夹下运行一下npm install

以上是express中对mongodb的配置，假设你本地没有装mongodb的数据库请到http://www.mongodb.org/downloads下载安装。