查看elm 后台node 代码 一直连不上mongodb，报错
MongoDB shell version v3.6.0 connecting to: mongodb://127.0.0.1:27017 2017-12-27T09:54:34.775+0800 W NETWORK [thread1] Failed to connect to 127.0.0.1:27017, in(checking socket for error after poll), reason: Connection refused 2017-12-27T09:54:34.778+0800 E QUERY [thread1] Error: couldn‘t connect to server 127.0.0.1:27017, connection attempt failed : connect@src/mongo/shell/mongo.js:237:13 @(connect):1:6 exception: connect failed
解决办法
brew services start mongodb
然后连接成功
Mac下mongodb connect failed 连接错误解决方法
原文：https://www.cnblogs.com/wupeng88/p/10393067.html