npm install mongodb --save

function Mongo(options) {
 this.settings = {
  url: 'mongodb://localhost:27017/jk',
  MongoClient:require('mongodb').MongoClient,
  assert:require('assert')
 };
 for(let i in options){
  this.settings[i] = options[i];
 }
 this._run = function (fun) {
  let that = this;
  let settings = this.settings;
  this.settings.MongoClient.connect(this.settings.url, function (err, db) {
   settings.assert.equal(null, err);
   console.log("Connected correctly to server");
   fun(db, function () {
    db.close();
   });
  });
 };
 this.insert = function (collectionName, data, func) {
  //增加数据
  let insertDocuments = function (db, callback) {
   let collection = db.collection(collectionName);
   collection.insertMany([
    data
   ], function (err, result) {
    if (!err) {
     func(true);
    } else {
     func(false);
    }
    callback(result);
   });
  };
  this._run(insertDocuments);
 };
 this.update = function (collectionName, updateData, data, func) {
  //更新数据
  let updateDocument = function (db, callback) {
   let collection = db.collection(collectionName);
   collection.updateOne(updateData
    , {$set: data}, function (err, result) {
     if (!err) {
      func(true);
     } else {
      func(false);
     }
     callback(result);
    });
  };
  this._run(updateDocument);
 };
 this.delete = function (collectionName, data, func) {
  //删除数据
  let deleteDocument = function (db, callback) {
   let collection = db.collection(collectionName);
   collection.deleteOne(data, function (err, result) {
    if (!err) {
     func(true);
    } else {
     func(false);
    }
    callback(result);
   });
  };
  this._run(deleteDocument);
 };
 this.find = function (collectionName, data, func) {
  //查找数据
  let findDocuments = function (db, callback) {
   // Get the documents collection
   let collection = db.collection(collectionName);
   // Find some documents
   collection.find(data).toArray(function (err, docs) {
    if (!err) {
     func(true,docs);
    }
    else {
     func(false, err);
    }
    callback(docs);
   });
  };
  this._run(findDocuments);
 };
}
module.exports = Mongo;

const Server = require("../server.js");

let server = new Server();

let server = new Server({url:"mongodb://localhost:27017/mydb"});

server.find("users",{username:"username"},function (bool,data) {
  if(bool){
   console.log("查询到数据为"+data.length+"条");
  }
  else{
   console.log(data);
  }
 });
});