node.js和express应用程序中未处理的错误事件

我一直在关注关于“使用PassportJS进行身份验证”的教程

并从他的回购协议下载了文件。我把终端指示我的包裹装进去。然后我尝试再次运行该应用程序，但收到了此消息

connect.multipart() will be removed in connect 3.0
visit https://github.com/senchalabs/connect/wiki/Connect-3.0 for alternatives
connect.limit() will be removed in connect 3.0
Express server listening on port 3000

events.js:66
        throw arguments[1]; // Unhandled 'error' event
                       ^
Error: failed to connect to [localhost:27017]
    at Server.connect.connectionPool.on.server._serverState (/Users/juangallardo/Desktop/PassportJS-Authentication-master/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/server.js:540:74)
    at EventEmitter.emit (events.js:115:20)
    at connection.on._self._poolState (/Users/juangallardo/Desktop/PassportJS-Authentication-master/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:140:15)
    at EventEmitter.emit (events.js:91:17)
    at Socket.errorHandler (/Users/juangallardo/Desktop/PassportJS-Authentication-master/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/connection.js:478:10)
    at Socket.EventEmitter.emit (events.js:88:17)
    at Socket._destroy.self.errorEmitted (net.js:335:14)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

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问题是我没有运行MongoDB

我发现了那个“问题”

然后获得了安装和运行mongo的说明

然后，您只需使用以下命令从终端启动mongo服务器

mongod

然后回到你的项目中，用

node app.js

node app.js