title: Am I 'allowed' to modify props in the constructor?
body: <p>They say you shouldn't modify the <code>props</code> in a React Component. Does that extend to modifying them in the constructor?</p>
  
  <p>Specifically,</p>
  
  <pre><code>export default class BookingForm extends React.Component {
  
      constructor(props) {
          // am I allowed to modify `props` here?
          super(props);
      }
  }
  </code></pre>
  
  <p>To be perfectly clear, I'm aware that JavaScript will allow me to do so, I'm asking if this is a bad design pattern that will cause me headache in the future.</p>
  
  <p>I want to re-format some of the props upon initialization; they won't change again after that.</p>