title: How to include a text input in a React component with its value specified?
body: <p>I need to include a text input in a React component, with its initial value passed from the component's props:</p>
  
  <pre><code> &lt;input value={this.props.value} type='text'/&gt;
  </code></pre>
  
  <p>But the input is not editable, and React complains:</p>
  
  <pre><code> Warning: Failed form propType: You provided a `value` prop to a form field without an `onChange` handler. This will render a read-only field.
  </code></pre>
  
  <p>So I add a onChange event handler:</p>
  
  <pre><code> &lt;input value={this.props.value} type='text' onChange={this.valueChanged} /&gt;
  </code></pre>
  
  <p>What should I do in the valueChanged handler to update the input value? Do I have to use state?</p>