nodejs returning result from functions - mysql

Question

Here's how I write my code
model\user.js
'user strict';
var sql = require('./../db.js');
//User object constructor
var User = function(user){
this.email = user.email;
this.name = user.name;
this.gender = user.gender;
this.profileImageType = user.profileImageType;
this.profileImage = user.profileImage;
this.accountType = user.accountType;
this.createdAt = new Date();
};
User.getCountByEmail = function (email, result) {
console.log("entering user.getCountByEmail with")
console.log(email)
sql.query("Select COUNT(*) AS userCount from users where email = ? ", email, function (err, res) {
if(err) {
console.log("error: ", err);
return result(err, null);
}
else{
console.log("user getCountByEmail returns")
console.log(res)
return result(null, res);
}
});
};
model\userController.js
'use strict';
var User = require('./user.js');
exports.list_all_users = function(req,res){
User.getAll(function(err,user){
console.log('controller')
if (err){
res.send(err);
}else{
console.log('res', user)
res.send(user)
}
});
};
exports.getCountByEmail = function(email,res){
User.getCountByEmail(email, function(err,user){
if (err){
console.log('error', err)
return res.send(err)
}else{
console.log('res', user)
console.log(user)
return user;
}
});
};
index.js
var userController = require('./../model/userController.js');
userController.getCountByEmail("miow#email.com",res,function(err,result) {
if (err){
console.log("34 err")
console.log(err)
}else{
console.log("imin userCount: " + result)
}
});
now in my index.js above, the line userController.getCountByEmail is executed, but I want the result to be accessible inside the function. Unfortunately, it seems the code
function(err,result) {
if (err){
console.log("34 err")
console.log(err)
}else{
console.log("imin userCount: " + result)
}
isn't being executed at all. I only got the line
res [ RowDataPacket { userCount: 1 } ]
imin
[ RowDataPacket { userCount: 1 } ]
which is inside userController.js. So how do I get the result from userController.js sent to index.js ?

Answer 1

function(err,result) {
if (err){
console.log("34 err")
console.log(err)
}else{
console.log("imin userCount: " + result)
}
is not executed because in your model/userController getCountByEmail your only pass two parameters (email, res). So when you call this function in your index.js your actually pass three parameters. with the third one being
function(err,result) {
if (err){
console.log("34 err")
console.log(err)
}else{
console.log("imin userCount: " + result)
}
I would do this:
model/userController
exports.getCountByEmail = function(email,res){
User.getCountByEmail(email, function(err,user){
if (err){
console.log('error', err)
return res.send(err)
}else{
console.log('res', user)
console.log(user)
res.send(user);
}
});
};
index.js
userController.getCountByEmail("miow#email.com",res)
But in general the controller take (req, res, next) as parameter and the res is used like a return because it returns a response to the server.