title: What is httpinterceptor equivalent in angular2?
body: <p>In angularjs, we have http interceptor</p>
  
  <pre><code>$httpProvider.interceptors.push('myHttpInterceptor');
  </code></pre>
  
  <p>with which we can hook into all http calls, and show or hide loading bars, do logging, etc..</p>
  
  <p>What is the equivalent in angular2?</p>