title: Should values ever be stored on the instance of a component?
body: <p>Can I ever do something like this? Does it avoid issues with asynchronous state changes?</p>
  
  <pre><code>class Widget extends React.Component {
  
    constructor () {
      this.value = '123';
    }
  
    render () {
      var hello = this.value;
      // ...
    }
  }
  </code></pre>