title: How to handle key event in Draft js
body: <p>if I want to handle input of character <code>*</code>, I can use <code>handleBeforeInput(str)</code>:</p>
  
  <pre><code>handleBeforeInput(str) {
      if (str !== '*') {
        return false;
      }
      // handling
      return true;
  }
  </code></pre>
  
  <p>if I want to handle input of <code>ENTER</code>, I can use the hook <code>handleReturn(e)</code></p>
  
  <p>but if I want to handle input of <code>DELETE</code>, how to do?</p>