title: What is the default transformResponse and transformRequest functions in $http
body: <p>I'm wanting to serialize incoming and outgoing params. I've discovered I can do so by changing <code>transformRequest</code> and <code>transformResponse</code> default methods in <code>$http</code> config. My question is this. What is the default code inside these two functions? For the life of me I can't find out where it's at. In order for me to successfully serialize the params, I need to know what the original functions looked like. I'm currently running Angular 1.5.X. Thanks.</p>
  
  <pre><code>angular.module('coolApp')
  .config(function ($httpProvider) {
    $httpProvider.defaults.transformRequest = function(data){
      // What is the default code here?
      // I need to add {security_token: 'secret_code'} to the request
      // data sent to the server
  
    }
  
    $httpProvider.defaults.transformResponse = function(data){
      // What is the default code here?
      // I need to remove the useless_params attribute in the response
    }
  });
  </code></pre>