node.js调用mangodb的操作还是有点繁琐的，为了简化底层操作，关注具体业务，我特意把MongoDB封装了一下，话不多说直接看代码

封装代码

let MongoClient = require('mongodb').MongoClient;
const url = "mongodb://127.0.0.1:27017/"

class Dbc { 
 
  constructor(dataName,colName)
  { 
    this.dataName = dataName
    this.colName = colName
  }

  //查询，使用Promise封装，查询后的数据操作在.then()中完成
  find(obj)
  { 
    let that=this

    return new Promise((resolve,reject) =>
    { 
      MongoClient.connect(url,{ useNewUrlParser:true},function (err,dbs) { 
        if (err)
        { 
          reject(err)
        }
        else
        { 
          let collection=dbs.db(that.dataName).collection(that.colName)
          collection.find(obj).toArray(function (err,data) { 
            if (err)
              reject(err)
            else
              resolve(data)
            dbs.close()
          })
        }
      })
    })

  }
  //插入一个对象
  insertOne(obj){ 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;

      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.insertOne(obj,function(err, res) { 
        if (err) throw err;
        console.log("文档插入成功:",res.result)
        dbs.close();
      })
    })
  }

  //插入一个对象数组
  insertMany(obj){ 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.insertMany(obj,function(err, res) { 
        if (err) throw err;
        console.log("插入的文档数量为: " + res.insertedCount)
        dbs.close();
      })
    })
  }
  //插入一个数组对象
  insertMany(obj){ 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.insertMany(obj,function(err, res) { 
        if (err) throw err;
        console.log("插入的文档数量为: " + res.insertedCount)
        dbs.close();
      })
    })
  }
  //删除一个，删除第一个满足对象
  deleteOne(setObj)
  { 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.deleteOne(setObj,function(err) { 
        if (err) throw err;
        console.log("文档删除成功" )
        dbs.close();
      })
    })
  }
  //删除所有满足条件的对象
  deleteMany(setObj)
  { 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.deleteMany(setObj,function(err,obj) { 
        if (err) throw err;
        console.log(obj.result.n + " 条文档被删除")
        dbs.close();
      })
    })
  }
  //更新一条数据，第一个满足条件的对象
  updateOne(whereObj,setObj)
  { 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.updateOne(whereObj,{ $set:setObj},function(err) { 
        if (err) throw err;
        console.log("文档更新成功")
        dbs.close();
      })
    })
  }
  //更新多条数据
  updateMany(whereObj,setObj)
  { 
    let that = this;
    MongoClient.connect(url,function(err,dbs){ 
      if (err) throw err;
      let collection=dbs.db(that.dataName).collection(that.colName)
      collection.updateMany(whereObj,{ $set:setObj},function(err,res) { 
        if (err) throw err;
        console.log(res.result.nModified + " 条文档被更新")
        dbs.close();
      })
    })
  }


}

module.exports={ 
  Dbc
}

调用代码

const { Dbc} = require("./mongodbc")
const  dbc  = new Dbc("mydb","user")
//添加
 var myobj =  [
        {  name: '菜鸟工具', url: 'https://c.runoob.com', type: 'cn'},
        {  name: 'Google', url: 'https://www.google.com', type: 'en'},
        {  name: 'Facebook', url: 'https://www.google.com', type: 'en'}
       ];
dbc.insertMany(myobj)
//删除type为en的数据
dbc.deleteMany({ type:"en"})
//修改
dbc.updateMany({ type:"en"},{ url:"这是被修改后的路径"})
//查询type为en的数据
dbc.find({ type:"en"}).then(data => { 
  console.log(data)
  })