title: React props from parent to children
body: <p>I'm a debutant with react, i read the doc. It's a general question.
  I understand how to pass a props from a child component to a parent component. But, I don't understand how to pass a props from a parent component to the child component. <a href="https://i.stack.imgur.com/i9DVx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/i9DVx.png" alt="react props"></a></p>
  
  <p>So in the picture, to pass a props from list to app, i do that : 
  in list component : </p>
  
  <pre><code>interface Props {
     onCreateDoc : () =&gt; void
  }
  </code></pre>
  
  <p>And in my app component : 
  I call list with the props :</p>
  
  <pre><code>&lt;List onCreateDoc={this.onCreateDocCb}/&gt;
  </code></pre>
  
  <p>And i implement the function : </p>
  
  <pre><code>onCreateDocCb = () =&gt;{
  // code of function
  }
  </code></pre>
  
  <p>But I don't know how to pass a props from app to form. How can i do that ?  Thank you</p>