Illustrate toggling a filter with an event

[deanrad]

Here:
https://codesandbox.io/s/seasonal-image-filter-vcvwl

Some thoughts - the 'toggle' mode is one way, but an important other way is:

channel.listen('xmas/apply', ({ payload: { checked } }) => {
   return checked ?? new Observable(xmasFilter).pipe(
        takeUntil(query('xmas/apply', {checked: false}))
  );
});