DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version

关于警告 ：

DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.

大致意思是连接mongodb数据库的链接解析器会在未来移除，要使用新的解析器，通过配置{ useNewUrlParser:true }来连接。

代码如下：

var MongoClient = require('mongodb').MongoClient
var url = 'mongodb://localhost:27017/testdb'// 数据库地址
 
module.exports = {
    getDB: function (callback) {
        MongoClient.connect(url, {useNewUrlParser:true},  function (err, db) {
            callback(db)   
        })
    }
}