observeEvents = {
const lastEvent = new Mutable();
const input = viewof slider;
const transaction = (e) => {
lastEvent.value = e;
input.value = yMap.get('value')
input.dispatchEvent(new Event('input'))}
const setMap = (e) => {
if( e.isTrusted ) yMap.set('value', input.value )}
input.addEventListener('input', setMap);
yMap.observe(transaction)
invalidation.then(() => {
input.removeEventListener('input', setMap)
yMap.unobserve(transaction)})
return lastEvent.generator }