Running node.js proccess step by step - node.js

Question

I was a PHP developer, I'm trying to write code using node.js for praticing. M am confuse about node.js when I execute my program, line of code jump to next line.
This is the part of my code:
//article.js
var article_model = require('../models/article_model');
var comment_model = require('../models/comment_model');
var list_article,list_comment;
app.set('views','./views/article/');
app.set('view engine','ejs');
app.get('/list_article',csrfProtection,function(req,res){
master_model.get_article(req,xparams,function(status,result,total_data){
list_article = result.data;
});
console.log(list_article);
master_model.get_comment(req,xparams,function(status,result,total_data){
list_comment = result.data;
});
console.log(list_comment);
var params = {
title : "Article List",
data_article : list_article,
};
res.render('content.ejs',params);
});
and then
//master_model.js
exports.get_article = function (req,hash, fn) {
var auths = {
user : api_server["auth_username"],
pass : api_server["auth_password"],
}
request.get({url:"http://myapi.com/article/latest", auth:auths } , function(err,httpResponse,body) {
if (!err && httpResponse.statusCode == 200) {
var temp = JSON.parse(body);
if (temp.status == 1){
result_data = {status:1, message : temp.message ,data : temp.data};
return fn(true,result_data,1);
}else if(temp.status == 0){
result_data ={ status:0, message : temp.message};
return fn(false,result_data,0);
}
}else{
result_data ={ status:0, message : "error, please try again"};
return fn(false,result_data,0); //something problem to API
}
})
};
exports.get_comment = function (req,hash, fn) {
var auths = {
user : api_server["auth_username"],
pass : api_server["auth_password"],
}
request.get({url:"http://myapi.com/comment/latest", auth:auths } , function(err,httpResponse,body) {
if (!err && httpResponse.statusCode == 200) {
var temp = JSON.parse(body);
if (temp.status == 1){
result_data = {status:1, message : temp.message ,data : temp.data};
return fn(true,result_data,1);
}else if(temp.status == 0){
result_data ={ status:0, message : temp.message};
return fn(false,result_data,0);
}
}else{
result_data ={ status:0, message : "error, please try again"};
return fn(false,result_data,0); //something problem to API
}
})
};
when i run my code, and open browser, output data is blank, when i refresh again my browser show ouput my data (artcile list, and commment list)
and i look my console if first run
output : {
id : 1
title : title 1..
...
..
}
undefined
If i refresh my browser again, all output complete to show (not show undefined)
My question:
How to make my code run the process step by step until the process end and deliver to views?
Any problem with my code?
Thanks!

Answer 1

To address your initial question properly, you can actually go step by step, using breakpoints. In the latest node 7 and now 6 you can use Chrome Dev Tools to debug a node application. You need to set some breakpoints and watch variables to help you understand:
execution order
the precise values of variables at key moments
I still think breaking the big program into smaller programmes would be helpful and reduce surprises, but learning to debug properly is also really useful!
You just run the program with node --inspect index.js, and then a link will be displayed on the console that you load up in Google Chrome Browser.
There is a more thorough guide, which might help.
The official documentation is also worth a read.