how to use inner's result in outer function in node.js

Question

currently,i learn node-mysql in node.js,but I meet a question,try a lot,i don't how to solve it ?

like this:

var express = require('express');
var app = express();
var mysqlcon=require('./testmysql');
var mysqlconn=mysqlcon.conn;
var http=require("http");
var url=require("url");
app.use('/sql',testExist).listen(3000);
function testExist(req,res,next){
    var query = url.parse(req.url,true).query;
    var name=query.name;
    mysqlconn.connect();
    var result=function(err, results){
    return results.length;
    }
   mysqlconn.query('select * from  user where name = ?',[name],result);
   mysqlconn.end();
   if(result>1)
      console.log('result:'+result)
   res.end("name is already exist!")
}

I want to get the inner function's result in outer function ,for example the length of such query will be 1(results.length==1),but i want to use the result in testExist(),we know that node use callback function,so that i can't get the inner result in outer function. So can any guys help me to solve it.

Answer 1

you need move the using code inside the callback.

function callback(err, results) {
  if(results.length >1) console.log('result:' + results.length);
  res.end("name is already exists!");
}
mysqlconn.query("select * from user where name= ?", [name], callback);