async / await node js mongo client

Question

我正在编写一个模块以使用等待功能来执行mongo数据库异步操作： https://github.com/Alexander-Herranz/async-await-mongoclient-es6-promisify

async / await native语句仅适用于节点＆gt; = v8。 我想验证这是最好的方法： 1）验证只有一个与数据库的开放连接（在类DB的单个实例中）。

2）确保只执行myMongoDB.collection（collectionName）一次，并将其传递给mongo db操作。

3）mongo客户端异步/等待管理的方法（从未使用过这种方式）

//test.js

require('dotenv').config()
const {Db} = require("./db/db")
const db = new Db(process.env.DB_NAME)

testMongoAPI()

function getRandomInt(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

async function testMongoAPI() {
  try {
    const dbGetCol = await 
       db.getCollection(process.env.COLLECTION_NAME)
    let query1 = {}
    query1.hola=getRandomInt(1,999)
    await db.insertInCollection(dbGetCol, query1)
    let query2 = {}
    query2.hola=getRandomInt(1,999)
    query2.uno="dos"
    await db.insertInCollection(dbGetCol, query2)
    let query3 = {}
    query3.hola=getRandomInt(1,999)
    query3.uno="dos"
    await db.insertInCollection(dbGetCol, query3)
    let query4 = {}
    query4.hola=getRandomInt(1,999)
    query4.uno="dos"
    await db.insertInCollection(dbGetCol, query4)
    let query5 = {}
    query5.hola=getRandomInt(1,999)
    await db.insertInCollection(dbGetCol, query5)
    let query6 = {}
    query6.hola=getRandomInt(1,999)
    await db.insertInCollection(dbGetCol, query6)
    let query7 = {}
    query7.hola=getRandomInt(1,999)
    await db.insertInCollection(dbGetCol, query7)
    await db.getOneFromQuery(dbGetCol, query2)
    let cond1 = {}
    cond1.uno="dos"
    await db.getAllFromQuery(dbGetCol, cond1)
    await db.listCollecton(dbGetCol)
    await db.dropCollection(dbGetCol)
  } catch(error){ console.log(error) }
}

和db.js

//db.js


    require('dotenv').config()
    const { MongoClient } = require('mongodb')
    const promisify = require('es6-promisify')


    let _connection

    const connect = (url) => {
      if (!process.env.MONGO_CONNECTION_STRING) {
        throw new Error(`Environment variable MONGO_CONNECTION_STRING must be set to use API.`)
      }
      let prom = promisify(MongoClient.connect)(url)
      console.log(prom)
      return prom
    };

    /**
     * Returns a promise of a `db` object. Subsequent calls to this function returns
     * the **same** promise, so it can be called any number of times without setting
     * up a new connection every time.
     */
    const connection = (url) => {

      if (!_connection) {
        _connection = connect(url)
      }
      return _connection
    }
    exports.connection = connection

    class Db {

        constructor(dbName) {
        this.dbName = dbName
        }

      async getCollection(collectionName) {
        try{
          const db = await connection(process.env.MONGO_CONNECTION_STRING+this.dbName )

          let getCol = await db.collection(collectionName)
          if (process.env.TEST=='TEST'){
            console.log('Database Name: '+this.dbName)
            console.log('1 TEST OK - '+collectionName+' - Database created!')
          }
            return getCol
        } catch(error) { console.log("getCollection DB Error!") }
      }

        async insertInCollection(collection, data) {
            try{
            let insert = await collection.insertOne(data)
            if (process.env.TEST=='TEST'){
              console.log('2- insertInCollectionDB OK')
              console.log(data)
            }
                return insert
            } catch(error) { console.log(" insertInCollectionDB Error!") }
        }

      async getOneFromQuery (collection, query){
        try{
          let result = await collection.find(query).limit(1).toArray()
          if (process.env.TEST=='TEST'){
            console.log('3- query One OK')
            console.log(result)
          }
          return result
        } catch(error) { console.log("queryDB Error!")}
      }

        async getAllFromQuery(collection, query){
            try{
          let result = await collection.find(query).toArray()
          if (process.env.TEST=='TEST'){
            console.log('4- query All OK')
            console.log(result)
          }
          return result
            } catch(error) { console.log("queryDB Error!")}
        }

      async listCollecton(collection){
        try{
          let list = await collection.find().toArray()
          if (process.env.TEST=='TEST'){
            console.log('5- List All elems in Collection OK');
            console.log(list)
          }
          return list
        } catch(error) { console.log( "listCollecton Error!")}
      }

        async dropCollection(collection){
            try{
          let drop = await collection.drop()
          if (process.env.TEST=='TEST'){
            console.log('6 - dropCollectionDB OK')
          }
          return drop
            } catch(error) { console.log("dropCollectionDB Error!")}
        }

    }

    exports.Db = Db