Skill v1.0.1

version: "1.0.1"

Use computed() when you need a derived value:

total = computed(() => this.items().reduce((sum, item) => sum + item.price, 0));

computed() is pure, cached, and should derive values such as totals, filtered lists, or status flags.

Use effect() only when a signal change must trigger an external side effect:

effect(() => {
  localStorage.setItem('theme', this.theme());
});

Typical uses include logging, localStorage synchronization, and DOM manipulation. Never update signals inside effect(); this can cause circular dependencies.

If you need dependent writable state that resets when its source changes, use linkedSignal() instead:

selectedItem = linkedSignal(() => this.items()[0] ?? null);

Rule of thumb: value transformation → computed(); interaction with something outside the signal graph → effect().