Lini ungekuwa ukitumia useReducer badala ya useState?

Question

Accepted Answer

`useReducer` inaongeza state-transitions katika chaguo moja la **pure reducer function**, badala ya kusambaza `useState` setters nyingi. Ni toleo la React linalojengwa la Redux pattern. ```jsx function reducer(state, action) { switch (action.type) { case "increment": return { count: state.count + 1 }; case "setStep": return { ...state, step: action.payload }; case "reset": return { count: 0, step: 1 }; default: return state; } } function Counter() { const [state, dispatch] = useReducer(reducer, { count: 0, step: 1 }); // describe WHAT happened, not HOW state changes: return ; } ``` ## Jinsi inavyofanya kazi Una `dispatch` **action** (object rahisi inayoeleza tukio). React inaita `reducer(currentState, action)` na inatumia kile kinachoundwa kama state mpya. Reducer ni **pure** (hakuna side effects, hakuna mutation), ambayo inafanya mantiki kuwa inayotabirika na enhetest isolada. ## Wakati wa kuupendelea juu ya useState - State inayofuata **inategemea uliopita** state kwa njia zisizosimple. - Maadili kadhaa **yanabadilika pamoja** (k.m. `count` + `step` + `error`). - Mantiki ya update ni ngumu vya kutosha kwamba ingekuwa kurudia kwa handlers. ```jsx // instead of 4 separate useState + 6 setters, one reducer owns it all ``` Bonus: `dispatch` ina **stable identity**, kwa hivyo kuipitia context au kwa watoto wenye memoization haisababishi re-renders. Kwa maadili rahisi, kujitegemea, `useState` safi bado ni wazi zaidi.