Depends on what kind of component just updated. If it&#x27;s a low level text field, it probably shouldn&#x27;t broadcast the change to anywhere else in the program. Instead it would invoke it&#x27;s &#x27;onChange&#x27; callback. This way, there are no extra dependencies for making the text field component work. The parent component always provides the onChange callback and takes action accordingly.<p>However, if the component that just updated is high level, like an entire page or something, then it&#x27;s reasonable to assume it&#x27;s a one-off controller component and you should feel free to broadcast messages and couple the component with other parts of the program.<p><a href="https:&#x2F;&#x2F;medium.com&#x2F;@dan_abramov&#x2F;smart-and-dumb-components-7ca2f9a7c7d0#.1na8fj54h" rel="nofollow">https:&#x2F;&#x2F;medium.com&#x2F;@dan_abramov&#x2F;smart-and-dumb-components-7c...</a>