Apa iku custom hooks lan carane nulis siji?

Question

Accepted Answer

A **custom hook** iku fungsi sing jenenge dimulai karo `use` lan sing njaluk hook liya kanggo **package lan baleni logika stateful** — tanpa ngowahi component tree mu (beda karo HOCs utawa render props). ```jsx // extract "fetch + loading + error" logic once, reuse everywhere function useFetch(url) { const [data, setData] = useState(null); const [loading, setLoading] = useState(true); const [error, setError] = useState(null); useEffect(() => { const ctrl = new AbortController(); setLoading(true); fetch(url, { signal: ctrl.signal }) .then(r => r.json()) .then(setData) .catch(e => { if (e.name !== "AbortError") setError(e); }) .finally(() => setLoading(false)); return () => ctrl.abort(); }, [url]); return { data, loading, error }; } // usage — the component stays declarative: function Profile({ id }) { const { data, loading, error } = useFetch(`/api/users/${id}`); if (loading) return ; return

{data.name}

; } ``` ## Sifat-sifat penting - Iku nuruti **Rules of Hooks** (njaluk ing tingkat paling dhuwur; mung saka components/hooks). - **State terpusat per panggilan.** Loro components sing nggunakake `useFetch` saben-saben entuk state independen dhewe — ngibagekake hook ora ibagekake data. - Konvensi: jeneng `useX` lan bali state + fungsi (asring array utawa obyek). ## Mangapa iku penting Custom hooks iku cara idiomatik kanggo ibagekake logika (data fetching, forms, subscriptions, media queries) ing React modern, nggedhe components cilik lan logika testable kanthi terisolasi.