title: HTTP request callback on Node JS
body: <p>Hi I am trying to get a response via a http using the callback method. But I get an error saying callback is not a function. </p>
  
  <pre><code> module.exports.ipLookup = function (res, callback) {
      var http = require('http');
      var str = '';
      var options = {
          host: 'ip-api.com',
          port: 80,
          path: '/json/',
          method: 'POST'
      };
      var str= "";
      var req = http.request(options, function (res) {
          res.on('data', function (body) {
              str += body;
          });
  
          res.on('end', function () {
              callback(str);
          });
      });
  
  
      req.end();
  
      return str;
  
      }
  </code></pre>
  
  <p>What is should to id return the json api response via ip-api.com. If anyone can help me on this it would be greatly appreciated.</p>