node基于async/await对mysql进行封装

'use strict';
const mysql = require( 'mysql' );
var pool = mysql.createPool( {
 connectionLimit : 50,
 host : '',
 user : '',
 password : '',
 database : '',
 multipleStatements : true //是否允许执行多条sql语句
} );
//将结果已对象数组返回
var row=( sql , ...params )=>{
 return new Promise(function(resolve,reject){
 pool.getConnection(function(err,connection){
 if(err){
 reject(err);
 return; 
 }
 connection.query( sql , params , function(error,res){
 connection.release();
 if(error){
 reject(error);
 return;
 }
 resolve(res);
 });
 });
 });
};
//返回一个对象
var first=( sql , ...params )=>{
 return new Promise(function(resolve,reject){
 pool.getConnection(function(err,connection){
 if(err){
 reject(err);
 return; 
 }
 connection.query( sql , params , function(error,res){
 connection.release();
 if(error){
 reject(error);
 return;
 }
 resolve( res[0] || null );
 });
 });
 });
};
//返回单个查询结果
var single=(sql , ...params )=>{
 return new Promise(function(resolve,reject){
 pool.getConnection(function(err,connection){
 if(err){
 reject(err);
 return; 
 }
 connection.query( sql , params , function(error,res){
 connection.release();
 if(error){
 reject( error );
 return;
 }
 for( let i in res[0] )
 {
 resolve( res[0][i] || null );
 return;
 }
 resolve(null);
 });
 });
 });
}
//执行代码，返回执行结果
var execute=(sql , ...params )=>{
 return new Promise(function(resolve,reject){
 pool.getConnection(function(err,connection){
 if(err){
 reject(err);
 return; 
 }
 connection.query( sql , params , function(error,res){
 connection.release();
 if(error){
 reject(error);
 return;
 }
 resolve( res );
 });
 });
 });
}

//模块导出
module.exports = {
 ROW : row ,
 FIRST : first ,
 SINGLE : single ,
 EXECUTE : execute 
}

const mysql = require('./mysql.js');
(async ()=>{
let s = await mysql.row(sql,params);
console.log(s);
})();