Hooks (useState, useEffect, useContext, na zaidi) ni vipengele vya React kwa kusimamia state na side effects katika functional components — na hufanya kazi sawa katika React Native. Kuelewa hooks muhimu ni jambo la lazima kujenga React Native components.
const [count, setCount] = useState(0); // state + setter; setting it re-renders
const [user, setUser] = ();
// useEffect runs side effects (data fetching, subscriptions) after render
useEffect(() => {
fetchData(); // runs after render
// optional CLEANUP (returned function) — runs on unmount / before re-running
const sub = subscribe();
return () => sub.unsubscribe(); // CLEAN UP (prevent leaks)
}, [dependency]); // dependency array → when to re-run
// → [] = run once on mount; [dep] = run when dep changes; none = every render
useEffect hushughulikia side effects (fetching data, subscriptions, timers) na dependency array inayodhibiti wakati inavyokimbia, na optional cleanup function (muhimu kwa kuzuia leaks).
useContext → consume context (shared data without prop drilling)
useRef → a mutable reference that persists across renders (e.g. reference a component,
store a value without re-rendering)
useMemo → memoize an expensive computed value (performance)
useCallback → memoize a function (avoid unnecessary re-creation/re-renders)
useReducer → manage complex state with a reducer
CUSTOM HOOKS → extract reusable stateful logic (e.g. useFetch, useAuth)
⚠️ Only call hooks at the TOP LEVEL of a component (not in conditions/loops/nested functions)
⚠️ Only call hooks from React components or custom hooks
→ These rules ensure hooks work correctly (React relies on call order).
Kuelewa React hooks ni jambo la lazima kwa React Native kwa sababu hooks ndiyo njia ya kawaida ya kusimamia state na side effects katika functional components, ambazo ndizo jinsi React Native apps za kisasa zinavyojengwa, kwa hivyo ni maarifa ya lazima kujua.
Hooks hufanya kazi sawa kabisa katika React Native kama katika React kwa web, ikifanya maarifa haya kuhamishika moja kwa moja. useState (kusimamia state, kuchochea re-renders) ni msingi kwa component yoyote yenye data inayobadilika. useEffect ni muhimu hasa: hushughulikia side effects (data fetching, subscriptions, timers) na dependency array inayodhibiti wakati inavyokimbia na optional cleanup function (muhimu sana kwa kuzuia leaks kwa unsubscribing/kusafisha) — kuelewa useEffect, dependency array yake, na cleanup ni jambo la lazima kwa kuwa side effects (kama fetching data wakati screen inavyopakia) ni za kawaida na kupata useEffect vibaya husababisha bugs (infinite loops kutoka dependencies zisizo sahihi, leaks kutoka cleanup iliyokosekana).
Kuelewa hooks zingine muhimu — useContext (kutumia shared data bila prop drilling), useRef (persistent mutable references), useMemo/useCallback (memoization kwa performance), useReducer (complex state), na custom hooks (kutoa reusable stateful logic kama useFetch au useAuth — pattern yenye nguvu ya code reuse) — hufunika toolkit ya kujenga components halisi.
Kuelewa kanuni za hooks (kuziita tu kwenye top level na tu kutoka kwa components/custom hooks, kwa kuwa React hutegemea call order) ni jambo la lazima kuepuka bugs zenye ujanja.
Kwa kuwa hooks ni utaratibu wa kawaida wa state na side effects katika React Native functional components za kisasa (na maarifa huhamishika moja kwa moja kutoka React), na kwa kuwa kuelewa hooks muhimu (hasa useState na useEffect na cleanup yake) na kanuni ni jambo la lazima kujenga components sahihi, kuelewa React hooks ni maarifa ya React Native yanayotumiwa mara kwa mara — msingi wa kujenga React Native components za kisasa, kitovu cha kusimamia state na side effects, na zinazohamishika moja kwa moja kutoka web React, ujuzi wa msingi kwa maendeleo ya React Native.