gistfile1.js

var http = require('http');

var base_url = 'http://letsrevolutionizetesting.com/challenge.json?id='
function challenge(id) {
  http.get(base_url+id, function(res) {
    var result = [];
    res.on('data', function(chunk) {
      result.push(chunk);
    });
    res.on('end', function(chunk) {
      result = JSON.parse(result.join(''));

      if (result['follow']) {
        var new_id = result['follow'].match(/\d+/)[0];
        console.log(new_id);
        challenge(new_id);
      } 
      else {
        console.log(result);
      }
    });
  }).on('error', function(e) {
    console.log("Got error: " + e.message);
  });
}

challenge('756775492');