title: dom ready event in React
body: <p>I have some components like below:</p>
  
  <p><em>Wrapper: wrap Loader and Page</em></p>
  
  <p><em>Loader: some animation</em></p>
  
  <p><em>Page: page content</em></p>
  
  <p>code like this:</p>
  
  <pre><code>&lt;body&gt;
    &lt;div id="app"&gt;&lt;/div&gt;
  &lt;/body&gt;
  
  class Loader extends Component {}
  
  class Page extends Component {}
  
  class Wrapper extends Component {
      render() {
          return (
              &lt;Loader/&gt;
              &lt;Page /&gt;
          );
      }
  }
  
  ReactDOM.render(&lt;Wrapper /&gt;, document.getElementById('app'));
  </code></pre>
  
  <p>I want hide Loader and show Page component after DOM has compeletely loaded.</p>
  
  <p>How should I write dom ready event in <strong>React</strong>?</p>
  
  <p>like jQuery: <code>$(window).on('ready')</code></p>