MongoNetworkError：首次连接时无法连接到服务器 [localhost:27017] [错误：连接 ECONNREFUSED 127.0.0.1:27017

Question

MongoNetworkError: failed to connect to server [localhost:27017] on first connect [Error: connect ECONNREFUSED 127.0.0.1:27017

如果我重新安装 mongodb，代码工作正常。我想要一个永久的解决方案

c[error:MongoNetworkError: failed to connect to server [localhost:27017] on first connect [Error: connect ECONNREFUSED 127.0.0.1:27017]

const mongoClient=require("mongodb").MongoClient
const state={
    db:null
}

module.exports.connect=function(done){
    const url="mongodb://localhost:27017"
    const dbname="r-kart"
    mongoClient.connect(url,(err,data)=>{
        if(err) return done(err)
        state.db=data.db(dbname)
        done()
    })
}
module.exports.get=function(){
    return state.db
}