title: How to use formValueSelector() of redux form to acces of the value of a button
body: <p>I use redux-from for create some form.</p>
  
  <p>Today, i need to create a form that it's dynamic. 
  More precisely, when the user click on a button some field are display.</p>
  
  <p>I have found this sample on the <a href="https://redux-form.com/6.0.0-rc.1/examples/selectingformvalues/" rel="nofollow noreferrer">documentation of redux-form</a>.
  In this sample, it is a checkbox. </p>
  
  <p>I try to do the same thing with a button but it does not work.</p>
  
  <p>Something to do for that works with a button ?</p>
  
  <p>For me, it is the same logic that for a checkbox</p>
  
  <pre><code>&lt;Field
    name="button"
    id="button"
    type='button'
    component={renderButton}
  /&gt;
  { button &amp;&amp;
     &lt;div&gt;
       test
     &lt;/div&gt;
  }
  
  
  const selector = formValueSelector( 'testFrom' );
  
  function mapStateToProps (state) {
      const button = selector( state , 'button' );
      return {
          button ,
      };
  }
  </code></pre>
  
  <p>Thanks for your help.</p>