To conditionally call the ancestor for `afterSet...` methods.<small><sup>*</sup></small>
use the _optional chaining_ operator.

    super.afterSetBar?.(value, oldValue);

<pre class="runnable readonly text 280">
class Simple extends Base {
    static getConfig() {
        return {
            className: 'ComponentBasics.view.component.Simple',

            bar_: null, // A get/set field

        }
    }
    afterSetBar(value, oldValue) {
        // Do important processing here.
    }
}
</pre>

<pre class="runnable readonly text 140">
class ExtendsSimple extends Simple {
    afterSetBar(value, oldValue) {
        super.afterSetBar?.(value, oldValue);
        // Do important processing here.
    }
}
</pre>
<br>
<small>* The framework doesn't actually create the `beforeSet...`, 
`afterSet...`, and `beforeGet...` methods. Instead, the framework
conditionally calls the methods using the chaining operator.</small>