title: Declare a functional component as "pure"
body: <p>How to signal to React that a functional component is "pure", as an equivalent of <code>React.PureComponent</code> for component classes?</p>
  
  <pre><code>function C(props) { 
    return &lt;var&gt;{props.n}&lt;/var&gt; 
  }
  </code></pre>
  
  <p><strong>without</strong> making it a class</p>
  
  <pre><code>class C extends React.PureComponent {
    render() {
       return &lt;var&gt;{this.props.n}&lt;/var&gt;
    }
  }
  </code></pre>