Module effects 

Structs

Dispose

Functions

effect

Runs f() immediately and returns its Dispose, registering cleanup on the current scope when one exists. Like scoped_effect, this runs on every call - for mount-once semantics use scoped_effect_once or disposable_effect.

effect_once

Mount-once effect: runs f only the first time this call site composes. Later recompositions return the original Dispose without re-running setup.

effect_once_with_key

on_unmount

Helper to register cleanup inside effect.