title: Call a method of the child component
body: <p>I have a nested child component like this:</p>
  
  
  
  <pre class="lang-html prettyprint-override"><code>&lt;app-main&gt;
      &lt;child-component /&gt;
  &lt;/app-main&gt;
  </code></pre>
  
  <p>My <code>appMain</code> component needs to invoke a method on child-component.</p>
  
  <p>How to invoke a method on the child-component?</p>