title: componentDidUpdate vs componentDidMount
body: <p>I need to make sure an input element is focused when the following is true:</p>
  
  <ul>
  <li>the DOM is available and </li>
  <li>properties got changed</li>
  </ul>
  
  <p>Question: Do I need to put my code in both <code>componentDidUpdate</code> and <code>componentDidMount</code> or just <code>componentDidUpdate</code> would be suffice?</p>
  
  <pre><code>    private makeSureInputElementFocused() {
          if (this.props.shouldGetInputElementFocused &amp;&amp; this.inputElement !== null) {
              this.inputElement.focus();
          }
  
      }
  
      componentDidMount() {
          this.makeSureInputElementFocused(); // &lt;-- do i need this?
      }
      componentDidUpdate() {
          this.makeSureInputElementFocused();
      }
  </code></pre>