title: Re rendering angular 7 component
body: <p>I got this this hierarchy of component. A parent component who got 2 child components. I want the first child component to update a property of the parent component, after that the second child component re render.
  I got main component with two child components: one with select html input and the second one a table of data, the data is coming from the main component as an input. The idea is when i change the selected value, i want to change the data in the main component so the data table can get the new data from the main component. 
  How can i do that?</p>
  
  <p>In the first child:</p>
  
  <pre><code>@Output() optionSelected = new EventEmitter&lt;string&gt;();
  </code></pre>
  
  <p>@Input() data;</p>
  
  <p>In the parent:</p>
  
  <pre><code> @Input() displayOption: string;
   @Output() dataToSelect 
  </code></pre>
  
  <p>When the displayOption updated , i want the second child re render</p>