Class EventSource<Q, T>

Event emitter class this class allow you to emit and handle events

@example:

interface EvDoIt extends BasicEvent {
  param: unknown;
}

function EvDoIt( e: EvDoIt ) : EvDoIt {
  return BasicEvent<EvDoIt>( e );
}

interface TestEventMap extends EventMap {
    doit: EvDoIt;
}

let ee = new EventSource<TestEventMap>(null);
ee.listen({
    doit: (e) => {
        console.log(e);
        e.preventDefault(); 
    },
});

ee.defaults({
    doit: (e) => {
        console.log('default handler for ', e.type, e.selection);
    },
})

ee.on('doit', (e) => {
    debugger;
})

const ev = EvDoIt({ param: 10 });
ee.emit('change', ev);
if (ev.defaultPrevented) {
    console.log('prevented');
}