raynos / observ Goto Github PK

Is it possible to remove a listener?

https://gist.github.com/Raynos/6383916

I was a bit surprised that observ/computed tries to get the value of each of it's dependent observables upon initiation. This is contrary to how observ values themselves work. Or am I misunderstanding something?

Hey,
I think it would be cool to integrate the combination of vtree and observ with https://github.com/dominictarr/scuttlebutt.
This shouldn't be too hard, since scuttlebutt has an API similar to observ.

Since reactivity is emerging pattern in JS ecosystem, wouldn't it be nice to come to common ground?
observable/observ are now the main alternative observable API, compared to the proposal.
If observ implemented Symbol.observable, it would enable interop and make one more step towards standard reactive pattern.

Hi,

Question; when onchange fires, would it be an idea to pass the "path" of the element that triggered the onchange? Or to in some other way be able to filter the event.

The use cases would perhaps be when dealing with multiple deep brances, when dealing with "live" data being pushed to the client, or when heavy manipulation of the data is done on the way to the view...

• non-functions can be added as listeners
• as per https://github.com/dominictarr/observable#signal, I think listeners should only be called if the value actually changes

I'd be delighted to propose a PR if you think either of those are valid thoughts.

Cheers 👍

It's possible to implement an efficient computed that does branch detection and only re-evaluates the computed function when it's real dependencies changes.

see http://www.youtube.com/watch?v=mVjpwia1YN4#t=12m32s for reference on this issue

Currently

var d = computed([a, b, c], function fn(a, b, c) {
  return a ? b : c
})

fn get's called when a is true and c has changed. In that call path it returns b and the result of d is the same.

If we could write something like

var d = cleverComputed(function () {
  return a() ? b() : c()
})

In this case d can internally remember that it depends on a and b in the a === true branch and will not re-call itself when c changes. However when a changes d will set its internal dependencies to a and c instead.

not sure how to do this without a global state machine.

cc @Matt-Esch