componentWillUnmount method
ReactJS lifecycle method that is invoked immediately before a Component
is unmounted from the DOM.
Perform any necessary cleanup in this method, such as invalidating timers or cleaning up any DOM Element
s that
were created in componentDidMount.
See: reactjs.org/docs/react-component.html#unmounting-componentwillunmount
Implementation
@mustCallSuper
@override
void componentWillUnmount() {
dispose();
}