Clarity on when / if I need to call .release() on an effect reference?

[bennadel]

I'm trying to understand the potential for memory leaks in Alpine.js when using the .effect() method for reactivity. I see that the .effect() method returns an effect "reference" which I can then explicitly release via .release(effectReference). But, I'm not entirely sure if calling this is mandatory to prevent memory leaks? Or, if it's only necessary when one wants to stop the effect byproducts while all the involved players are still active in the app?

I took a look at the x-effect directive and I see that there is no use of .release() in any kind of .cleanup() call, which makes me think that it's not necessary for memory leak prevention.

What are people using for general guide-lines in terms of releasing effects?

[ekwoka]

x-effect cleans it up (though you make me worry). the effect utility passed to directives auto registers the release to the cleanup of the directive.

The effect will stick around so long as the data exists.

And you can potentially get into contexts where effects and data make a web of stuff where only one thing is directly used but it keeps a bunch of stuff around.

You should clean up your manually created effects (with Alpine.effect) once you no longer need them. It will be much harder to hunt down the cause of such a web of effects if you just ignore it for later.

[bennadel]

Ah, ok - I didn't realize that the effect passed into the Directive was different than the one on Alpine.effect(). So, if I'm hearing you correctly, as long as I use this one:

Directive( element, metadata, { effect } )

... then I do not have to worry about releasing it (as long as it's OK that the effect stays around for the duration of the host element?

[ekwoka]

Yes.

[bennadel]

Just for cross-reference, this came up in my blog post about creating an x-input directive for binding one scope value to another. I needed to propagate changes and was using Alpine.effect(). I'll go back and update my code to use the effect passed into the directive.

[bennadel]

It's possible that I am going about this all wrong - I'm still trying to learn how to use Alpine.js. My initial thought was to pass the values into the component constructor, like:

<div x-data="CustomRange({ min: 1, max: 100, step: 5 })">

And this would handle the initial rendering fine. But, then I wasn't sure how to react to changes in the configuration. Meaning, what if the max needed to be changed to 200 - I wasn't sure how to handle that since the CustomRange() constructor call essentially breaks the connection with the parent context (since simple values are pass-by-value).

This is not the best example, since these values are hard-coded; but, just imagine any scenario in which you need to pass a value into a component; and that value could potentially change over time. Maybe something like a "Latest Tweet" widget:

<div x-data="LatestTweet" x-input:username="selectedUser">

Then, in the calling context, you could choose between any number of users, and the LatestTweet component would have to make a new fetch() call in the background.

[bennadel]

When I was originally thinking about stuff like this, I knew that I had other options like:

<div x-effect="updateInputs( ... )">

and

<div x-init="$watch( ..., updateInputs( .. ) )">

But, those all felt wonky to me. One of the things that always shocks me a bit is how many people in the Alpine world are comfortable putting full-on fetch() calls inside their HTML markup. Maybe that's my Angular background coming out, but I still want my markup to be as clean / sparse as possible. So, what I was trying to do was build abstractions over these lower-level things in an effort to keep the HTML as clean as possible.

[ekwoka]

I put very little in the attributes, like if it isn't just a single expression...it is probably gonna go into a component script.

There's a few different approaches that handle that situation. Like your custom directive could take the object expression for the config, and you can use an effect to update the local scope within that. Hell, it could set up the whole component so you don't even need the x-data.

[bennadel]

I think a core part of the problem that I was trying to overcome was having to have the child component depend on the name of the value as defined in the parent component. If I was going to perform the .effect() inside the child component, it seems the child component would have to know the name, such as this.selectedUser in the x-data="LatestTweet" example. But then, if the parent component changed that to this.user, I'd have to go and change the .effect() logic in the LatestTweet component as well.

Anyway, I appreciate all the feedback - it seems there are a lot of different ways to accomplish something like this. It seems to come down to which trade-offs you want to make / avoid.

[ekwoka]

Surely, the x-input implemented there is already doing that anyway.