Alpine.effect() does not trigger when combined with Alpine.store()

[boustanihani]

I assume the Alpine.store() is reactive by nature.
I just need a function to get triggered when an array of images gets empty, the array is already inside the Alpine.store.
Shouldn't the following code work (without the need of using Alpine.reactive() ?
Everything is working great, except the code inside Alpine.effect() =>

Alpine.store('images') = [];

Alpine.effect(() => {
    if (Alpine.store('images').length == 0) { doSomething() }
})