title: Preventing child prop update if parent component unmounts
body: <p>After upgrading to the latest react-redux (v7), I'm having issues with prop updates. Here's an example:</p>
  
  <pre><code>const shouldRender = WrappedComponent =&gt; props =&gt; props.shouldRender ? &lt;WrappedComponent {...props} /&gt; : null
  
  const MyComponent = compose(
    connect(state =&gt; ({ shouldRender: Boolean(state.page) })),
    shouldRender,
    connect(state =&gt; ({ title: state.page.title }))
  )(MyBaseComponent)
  
  &lt;MyComponent /&gt;
  
  store.dispatch({ type: 'CLEAR_STATE' }) // =&gt; Sets state.page to null
  </code></pre>
  
  <p>In v5 of react-redux, when state.page is reseted to it's initial state (null), the <code>shouldRender</code> HOC will render null instead of the component and thus not try to get the state.page.title in the next line.</p>
  
  <p>After upgrading to v7, the same scenario still triggers <code>state.page.title</code> and throw a error (cannot get title of undefined).</p>
  
  <p>The most simple solution would be to not rely on a parent HOC and guard the props (<code>title: state.page &amp;&amp; state.page.title</code> but this will introduce loads of guards everywhere in my code.</p>
  
  <p>How can I prevent the last connect mapStateToProps from happening if the parent already unmounts (thus prop change on children is not needed as it will get unmounted anyway).</p>