title: Callback is not a function
body: <p>I am trying to retrieve a json object to use it in another module, but I have a problem with callback. I have the error "callback is not a function". I use callback because my variable description is undefined, so i guess it's a problem of asynchronous.</p>
  
  <p>Could you help me plz :)</p>
  
  <pre><code>var leboncoin = function () {
      var http = require('http')
      var bl = require('bl')
  
      http.get("http://www.website.com", function (response, callback) {
          response.pipe(bl(function (err, data) {
              if (err) {
                  return console.error(err)
                  callback(err);
              }
              var data = data.toString()
  
              var brand = ...
              var model = ...
              var releaseDate = ...
              var km = ...
              var fuel = ...
              var gearbox = ...
  
              description.Brand = brand;
              description.Model = model;
              description.Year = releaseDate;
              description.KM = km;
              description.Fuel = fuel;
              description.Gearbox = gearbox;
  
              callback(description);
              return (description)
  
              /*console.log(description.Brand);
              console.log(description.Model);
              console.log(description.Year);
              console.log(description.KM);
              console.log(description.Fuel);
              console.log(description.Gearbox);*/
  
          }))
      })
  }
  
  exports.leboncoin = leboncoin;
  </code></pre>
  
  <hr>
  
  <pre><code>var module = require('./leboncoin');
  var res = module.leboncoin();
  
  console.log(res);
  </code></pre>