server.js

// server.js
// where your node app starts

// init project
var express = require('express');
var app = express();
const url = require('url');
var useragent = require('express-useragent');

// enable CORS (https://en.wikipedia.org/wiki/Cross-origin_resource_sharing)
// so that your API is remotely testable by FCC 
var cors = require('cors');
app.use(cors({optionSuccessStatus: 200}));  // some legacy browsers choke on 204

// http://expressjs.com/en/starter/static-files.html
app.use(express.static('public'));
app.use(useragent.express());

// http://expressjs.com/en/starter/basic-routing.html
app.get("/", function (req, res) {
  res.sendFile(__dirname + '/views/index.html');
});


// your first API endpoint... 


app.get("/whoami", function (req,res) {
  var ip = req.headers['x-forwarded-for'] || 
     req.connection.remoteAddress || 
     req.socket.remoteAddress ||
     (req.connection.socket ? req.connection.socket.remoteAddress : null);
  var lan = req.headers["accept-language"];
  res.json({"IP": ip.slice(0,ip.indexOf(',')) ,'language': lan.slice(0,lan.indexOf(',')), 'OS ': req.useragent.os});
  
  
});



// listen for requests :)
var listener = app.listen(process.env.PORT, function () {
  console.log('Your app is listening on port ' + listener.address().port);
});