Allow filters to express implicit dependencies

[nevir]

myFilter = {
  filter:    ... // The filter function.
  extraDeps: ... // A function that returns an array of observers.
};

An example of where I'm using it: https://github.com/Polymore/more-routing/blob/master/polymer-expressions.html#L25-33

[jmesserly]

I wonder if we could just put the extraDeps property on function itself? Since in JS that's no big deal. That way the filter would be callable.

[nevir]

Yeah, that would jive better w/ filters within elements too. I was trying to follow along with toDOM/toModel - not sure whether it's worth it though?

[jmesserly]

I think toDOM/toModel is for two-way bindings. Conceivably they could have different "extra deps"?

[jmesserly]

did you figure out:

// TODO(nevir): Why does this only trigger once if we return a PathObserver?

... seems worth addressing (or at least understanding)

I added my $0.02 but would be great to get thoughts from @rafaelw if he's around :)

[jmesserly]

btw, the general idea here seems reasonable to me (give filters an easy a way to signal other dependencies they might have)

[nevir]

...I didn't figure that PathObserver vs addPath thing, either. It seems to only occur for a compound observer that already has some paths (and some other conditions I haven't been able to nail down yet...)

[rafaelw]

Sorry for the latency.

I just talked with Ian in person. I think the question here is whether
Scott wants to add this feature. If he does, I'm happy to review this.

That said, it seems to me like this is a bit of a band-aid over a larger
problem and since we are holding off no addressing the larger problems, I'd
be tempted to not make stop-gap fixes that we'll have to unroll or support
going forward.

On Tue, Sep 9, 2014 at 12:33 PM, John Messerly notifications@github.com
wrote:

did you figure out:

// TODO(nevir): Why does this only trigger once if we return a PathObserver?

... seems worth addressing.

I added my $0.02 but would be great to get thoughts from @rafaelw
https://github.com/rafaelw if he's around :)

—
Reply to this email directly or view it on GitHub
#53 (comment)
.