app.js

'use strict';

var express = require('express');
var bodyParser = require('body-parser');
var cheerio = require('cheerio');
var request = require('request');
var port = process.env.PORT || 1337;
var router = express.Router();
var app = express();

app.use(bodyParser.urlencoded({
  extended: true
}));
app.use(bodyParser.json());

var coinList = [];
var target = 'http://coinmarketcap.com/';

router.use(function(req, res, next) {
  next();
});

router.get('/', function(req, res) {
  res.json({
    message: 'Welcome to coins-api! Documentation for querying the API is available here: https://github.com/xasos/Coins.'
  });
});

router.route('/coins/:ticker?')
  .get(function(req, res) {
    var coinTicker = req.params.ticker;

    request(target, function(err, resp, body) {
      if (!err && resp.statusCode == 200) {
        var $ = cheerio.load(body);
        var currentTime = Date.now();

        $('tr').each(function(i) {
          if ($(this).attr("id")) {
            var coinName = $(this).attr("id").slice(3);
          }

          var pos = $(this).find('td').eq(0).text().trim();

          var marketCap = $(this).find('td').eq(2).text().trim();
          marketCap = marketCap.slice(2).replace(/,/g, "");

          var price = $(this).find('td').eq(3).text().trim();
          price = price.slice(2).replace(/,/g, "");

          var ticker = $(this).find('td').eq(4).text().trim();
          ticker = ticker.split('\n').slice(1, 2).join('\n').trim();

          var volume = $(this).find('td').eq(5).text().trim();
          volume = volume.slice(2).replace(/,/g, "");

          var delta24hr = $(this).find('td').eq(6).text().trim();
          delta24hr = delta24hr.slice(0, -2);

          var coins = {
            name: coinName,
            position: pos,
            price: price,
            currency: "usd",
            marketCap: marketCap,
            ticker: ticker,
            volume: volume,
            delta24hr: delta24hr,
            timestamp: currentTime
          };
          
          if (coinTicker) { // Check if user supplied a specified ticker in URL
            if (coins.name === coinTicker) {
              var individualCoin = key;
              coinList.push(key);
            }
          }
          else if (coinName) { // Else check if coinName is valid
            coinList.push(coins);
          }

        });
      }
    });
    res.json(coinList);

  });

router.route('/coins/:ticker?/price/:currency')
  .get(function(req, res) {
    var ticker = req.params.ticker;
    var currency = req.params.currency;
    var coins;

    var requestURL = 'http://freecurrencyconverterapi.com/api/v3/convert?q=USD_' + currency + '&compact=ultra';

    request(target, function(err, resp, body) {
      if (!err && resp.statusCode == 200) {
        var $ = cheerio.load(body);        

        $('tr').each(function(i) { 
          if ($(this).attr("id")) {
            coinName = $(this).attr("id").slice(3);
          }

          price = $(this).find('td').eq(3).text().trim();
          price = price.slice(2).replace(/,/g, "");          

          if (coinName == ticker) {
            coins = {
              name: coinName,              
              price: price
            }
          };

        });
             
        request(requestURL, function(error, response, body) {
          if (!error && response.statusCode == 200) {
            // Get first property from returned data
            var firstProp;
            for (var key in body) {
              if (body.hasOwnProperty(key)) {
                firstProp = body[key];
                break;
              }
            };

            // Get new price and return
            var newPrice = coins.price * body.firstProp;
            res.send({
              price: newPrice
            });
          }
        });

      }
    });
  });

app.use('/', router);
app.listen(port);
console.log('Listening on port ' + port);