Added stuff

-Added comments
-Tested freeport but failed in the current build

index.js

@@ -1,40 +1,63 @@
+/* QR-FILETRANSFER done in NodeJS
+ *
+ *  Inspired from @claudiodangelis qr-filetransfer written in Go
+ *  @claudiodangelis https://github.com/claudiodangelis
+ */
+
+//Initialising dependencies
 var express = require('express');
 var qrTerminal = require('qrcode-terminal');
 var chalk = require('chalk');
 var fs = require('fs');
-var localIpV4Address = require('local-ipv4-address');
+var localIpV4Address = require("local-ipv4-address");
+
+//Calling local scripts
 
 var misc = require("./lib/misc.js");
 var constants = require("./lib/constants.js");
 
+//Initialising express
 var app = express();
 
-const port = 3000 || process.env.PORT;
+//Defining constants for path and port
 const pathInitial = __dirname + "/";
 var pathTotal = pathInitial + process.argv[2];
 
-var ipv4 = "http://192.168.1.2:3000";
+//Using the constant values in lib/constants.js
+//TODO: Constant values shouldn't be usued at all. It could break in any other device.
 
+var ipv4 = constants.ipv4;
+var fPort = constants.port;
+
+//Getting the localIP of the device
 localIpV4Address().then(function(ipAddress){
     ipv4 = ipAddress;
 });
 
+//Defining a string in the form http://ip-address:port for the qr generation
+const finalIP = ipv4 + ":" + fPort;
 
+//Checking the arguments passed
 if(process.argv.length != 3) {
   console.log(chalk.red(":/ Something's missing in the arguments"));
   console.log(chalk.green("It should be something like node index.js i_am_so_great.pdf"));
   process.exit(0);
 }
 
+//Checking if the file exists
 if(!fs.existsSync(pathTotal)) {
   console.log(chalk.red("The file does not exist, Please check the file path again"));
 }
 else {
 
-  app.listen(port, (req,res) => {
-  //console.log("Server is live");
+  //Initialising the server
+  app.listen(fPort, (req,res) => {
+  console.log("Server is live at port" + fPort);
   misc.header();
-  qrTerminal.generate(ipv4);
+
+  //Generating the qrcode
+  qrTerminal.generate(finalIP);
+  console.log(finalIP);
 
 });
 

lib/constants.js

@@ -1,3 +1,7 @@
 module.exports = {
-  owner: "Sagar"
+  owner: "Sagar",
+  port: "3000",
+  ipv4: "http://192.168.1.2"
 }
+
+//Incase localIPv4Address fails, Assign the local IP of your machine from here

package.json

@@ -12,6 +12,8 @@
     "chalk": "^2.3.2",
     "express": "^4.16.3",
     "figlet": "^1.2.0",
+    "freeport": "^1.0.5",
+    "get-port": "^3.2.0",
     "local-ipv4-address": "0.0.2",
     "qrcode-terminal": "^0.12.0"
   }