title: react js error in index file Cannot update a component Issue
body: <p>There is a serious issue in my react testing application. Please check the below error</p>
  <pre><code>index.js:1 Warning: Cannot update a component (`App`) while rendering a different component (`AppContainer`). To locate the bad setState() call inside `AppContainer`,
  </code></pre>
  <p><a href="https://i.stack.imgur.com/48HGc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/48HGc.png" alt="enter image description here" /></a></p>
  <p>this is my index.js code</p>
  <pre><code>    import React from 'react';
  import ReactDOM from 'react-dom';
  import App from &quot;containers/App&quot;;
  import * as serviceWorker from './serviceWorker';
  ReactDOM.render(&lt;App/&gt;, document.getElementById('root'));
  serviceWorker.unregister();
  </code></pre>
  <p>what is this issue. how can i fix this</p>