Encapsulate node.js code in a function - node.js

Question

So far I have the below code which I need to get the id from a JSON object:
var http = require("http");
var fs = require('fs');
//var bodyParser = require("body-parser");
//var moment = require("moment");
var options = {
"method" : "GET",
"hostname" : "xxx.xxx.xxx.xxx",
"port" : "18080",
"path" : "/api/v1/applications/"
};
var req = http.request(options, function (res) {
var chunks = [];
res.on("data", function (chunk) {
chunks.push(chunk);
});
res.on("end", function () {
var body = JSON.parse(Buffer.concat(chunks));
var arrFound = Object.keys(body).filter(function(key) {
if (body[key].name.indexOf("TestName") > -1) {
return body[key].name;
}
}).reduce(function(obj, key){
obj = body[key].id;
return obj;
}, {});;
//console.log("Name: ", arrFound);
console.log("ID: ", arrFound);
});
});
req.end();
I know it's reading the id as I currently write it out to the console(console.log("ID: ", arrFound);).
What I would like to do is have this available for use in other parts of my program. I assume I need to do something like encapsulate it in a function that I can call but node.js is new to me and I'm not entirely sure how/what to do.
Can anybody advise how to do this or point me to some resource that might help?

Answer 1

You should research the module pattern and exports. You are right, the basic idea is to export your code as a function. Based on how you've approached this, it should take a callback function. I've made a naive attempt with what you have.
Notice I pass a null as the first argument to the callback function. It is conventional when using callbacks in node to use the first argument for errors. You probably need some error handling.
Having said that, you night look into some libraries like requests, or the ES6 fetch function. These will allow you to organize your code more neatly. You'll probably wind up using promises instead of callbacks.
var http = require("http");
var fs = require('fs');
//var bodyParser = require("body-parser");
//var moment = require("moment");
var options = {
"method" : "GET",
"hostname" : "xxx.xxx.xxx.xxx",
"port" : "18080",
"path" : "/api/v1/applications/"
};
exports.getId = function(callback) {
var req = http.request(options, function (res) {
var chunks = [];
res.on("data", function (chunk) {
chunks.push(chunk);
});
res.on("end", function () {
var body = JSON.parse(Buffer.concat(chunks));
var arrFound = Object.keys(body).filter(function(key) {
if (body[key].name.indexOf("TestName") > -1) {
return body[key].name;
}
}).reduce(function(obj, key){
obj = body[key].id;
return obj;
}, {});;
//console.log("Name: ", arrFound);
callback(null, arrFound));
});
});
req.end();
}
You call it like this:
exports.getId(function(err, id){
console.log(id)
})