"Observble" vs "Observer"?

[grandsong]

If A watch/observe B, I would name A "Observer" and B "Observble".

But, in the official document,

An observable is an object that can be initialized to watch the state of a document.

and

observable.observe(doc, (diff, before, after, local, changes) => {
  // ...
}

Why "observable"? Why not "observer"?

[ept]

Yeah this class is perhaps mis-named. The proposed repository API (#486) will supersede this observable API anyway, so that will be an opportunity to clean up the naming.