ability to observe a particular element's connectedness.

[trusktr]

For example,

const observer = new ConnectionObserver((connected) => {
  if (connected) console.log('connected')
  else console.log('disconnected')
})

observer.observe(el)

Or, we already have EventTarget in the web, why did we need a new API shape (MutationObserver) again????

el.addEventListener('connected', () => console.log('connected'))
el.addEventListener('disconnected', () => console.log('didconnected'))

[ox-harris]

It's an interesting thing to do. Will share what I find possible with realdom

[ox-harris]

@trusktr you can now observe cross-roots mutations. Just set options.subtree to cross-roots.

Also, we've now introduced a help method for observing an element's connectedness: the .track() method. (But maybe there's a better name, dunno.)

const p = document.createElement('p');
realtime(document).track(p, state/*Bool*/ => {
    console.log('connectedness:', state);
});
document.appendChild(p); // connectedness: true
p.remove(); // connectedness: false

[ox-harris]

Next would be exploring an event model. I really do like that one.