Write array object to JSON in node.js - node.js

Question

I am trying to write some items I pushed into an array into a JSON file in node.js but I can't figure out how to wait for the array to contain the items before writing the JSON file. As a result the file is always empty. Do i need to have a callback? If so, how? NB:I'm still new to node.js
This is the code below:
var getLinks = require('./news_archive/news_links.js');
var request = require('request');
var cheerio = require('cheerio');
var fs = require('fs');
var saveNews = './news_archive/news.json';
var jsonObj = [];
var i;
var number_of_links = getLinks.links.length;
for(i=0; i<number_of_links; i++){
//GET ARTICLE LINK FROM link.js
var url = "http://www.times.co.sz/"+getLinks.links[i];
request(url, function(err, resp, body){
var $ = cheerio.load(body);
//GET ARTICLE HEADLINE
var storyHeadline = $('#article_holder h1');
var storyHeadlineText = storyHeadline.text();
//GET DATE POSTED
var datePosted = $('.metadata_time');
var datePostedText = datePosted.text();
//GET ARTICLE REPORTER'S NAME
var reporterName = $('.article_metadata a');
var reporterNameText = reporterName.text();
//GET ARTICLE SUMMARY
var fullStory = $('#article_body span');
var fullStoryText = fullStory.text();
//PUSH ITEMS TO jsonObj ARRAY
jsonObj.push({
id: i,
storyHeadline: storyHeadlineText,
datePosted: datePostedText,
reporterName: reporterNameText,
fullStory: fullStoryText
})
});
} //END for LOOP
//WRITE TO news.json file
fs.writeFile(saveNews, JSON.stringify(jsonObj, null, 4), function(err) {
if(err) {
console.log(err);
} else {
console.log("JSON saved to " + saveNews);
}
});

Answer 1

The issue is that request is asyncronous and you cannot use syncronous loop to iterate through. You can use async lib for that
var getLinks = require('./news_archive/news_links.js');
var request = require('request');
var cheerio = require('cheerio');
var fs = require('fs');
var saveNews = './news_archive/news.json';
var number_of_links = getLinks.links.length;
var async = require('async');
async.times(number_of_links, function (i, next) {
var url = "http://www.times.co.sz/"+getLinks.links[i];
request(url, function(err, resp, body){
var $ = cheerio.load(body);
//GET ARTICLE HEADLINE
var storyHeadline = $('#article_holder h1');
var storyHeadlineText = storyHeadline.text();
//GET DATE POSTED
var datePosted = $('.metadata_time');
var datePostedText = datePosted.text();
//GET ARTICLE REPORTER'S NAME
var reporterName = $('.article_metadata a');
var reporterNameText = reporterName.text();
//GET ARTICLE SUMMARY
var fullStory = $('#article_body span');
var fullStoryText = fullStory.text();
//PUSH ITEMS TO jsonObj ARRAY
next(err, {
id: i,
storyHeadline: storyHeadlineText,
datePosted: datePostedText,
reporterName: reporterNameText,
fullStory: fullStoryText
});
});
}, function (err, res) {
// do not forget to handle error
fs.writeFile(saveNews, JSON.stringify(res, null, 4), function(err) {
if(err) {
console.log(err);
} else {
console.log("JSON saved to " + saveNews);
}
});
})