Nested effects.

[kethan]

Wow! Awesome I was expecting a micro signal from you there it is. I have an issue if I nest effects like this:

const counter = signal(1);
const double = computed(() => counter.value * 2);
const tripple = computed(() => counter.value * 3);

effect(() => {
  console.log(double.value);
  effect(() => {
    console.log(tripple.value);
  });
});
counter.value = 20;

The triple value is consoled 3 times.

[WebReflection]

can you please try again with latest?

[kethan]

Nope, now it logs twice.
const dispose = effect(() => console.log(fullName.value))
Is there a dispose function like in preact signals?

[WebReflection]

I think batch works nested but effects has no special logic there … will create a test case and see how preact works and fix it, but probably not today. Thanks for the issue

[WebReflection]

@kethan I can confirm preact does exactly the same, it logs:

2
3
40
60
60

After all computed caches results so it's not called twice, so I think this is expected because inner effect should execute before outer effect and when outer effect is invoked the inner one is still an effect, hence the double 60.

However, changing the test like this:

const counter = signal(1);
const double = computed(() => {
  console.log('double');
  return counter.value * 2
});
const tripple = computed(() => {
  console.log('triple');
  return counter.value * 3;
});

effect(() => {
  console.log(double.value);
  effect(() => {
    console.log(tripple.value);
  });
});
counter.value = 20;

Shows the following:

double
2
triple
3
double
triple
40
60
60

meaning the computed value 60 is executed only once. There is a tiny discrepancy here with preact, which would instead show:

double
2
triple
3
double
40
triple
60
60

but this has nothing to do with your concern, it's just a matter of when the computed gets cached. Here it's computed right away for each registered callback per that signal, in preact is computed after the inner effect happens. Apparently usignal here is "correct" though so I think we can close this?

[WebReflection]

reopening, as tests show preact got it as wrong as I did (using preact as reference) but solid got it right, and now I understand what the dispose question was about ... will think about it, as indeed solid behavior sounds about right.

where does preact exposes dispose though? is it in the signals-core module? and are developers supposed to invoke it manually?

[kethan]

Look for an example: https://codesandbox.io/s/signal-clean-effect-torrpe?file=/src/index.js

[kethan]

And btw using your codebase I made a lib that can do both Observable and Signal (like solid, voby, knockout.js, etc).

https://github.com/kethan/ulive
Any feedback or suggestion is highly appreciated.

Thanks.

[WebReflection]

@kethan so ... you removed my copy right from code you copy pasted from this repository and you want a review of "your work"? this is not how licenses work mate, use a dependency and/or contribute here, don't do that shit instead!

there's a difference between inspired and stolen

[WebReflection]

https://github.com/WebReflection/usignal/blob/main/LICENSE

[kethan]

Oops sorry i will add that. But I did mention your repo and name. I will add that in code too .

[WebReflection]

@kethan fully fixed and tested in the fully rewritten 0.3.0 🥳 thanks for filing this issue, it helped me a lot figuring out many things 👋