Menene `useEffect` kuma yaushe yake aiki?

Question

Accepted Answer

`useEffect` yana aiki **tasukan gida** — aiki wanda ke fita wajen rabe React, kamar karfin bayani, lajosawa, agajiya, ko sabunta DOM ba tare da wasu hanya ba. Yana aiki **bayan** muhimmin bambanta render, yana janye tasukan gida daga jikin render (render dole ne ya kasance mai tsafi).

## Tsarin dogara ya sarrafa lokaci

```jsx
useEffect(() => {
  document.title = `Count: ${count}`;
}, [count]); // ← dependency array
```

- **`[count]`** → yana aiki bayan fari render da kuma lokacin da `count` ya canja.
- **`[]`** (wofi) → yana aiki **kamu** bayan wullakawa (kyau ga saita kamu ɗaya).
- **barre** → yana aiki bayan **kowa** render (ba sosai abin da kika so ba).

## Tsafi: dawo da aikin

Idan tasuke tara wani abu da ya buƙa fage, dawo da aikin tsafi. React yana kira shi kafin jiya na tasuke kuma lokacin da muhimmin rasa:

```jsx
useEffect(() => {
  const id = setInterval(() => setN(n => n + 1), 1000);
  return () => clearInterval(id); // cleanup → prevents a leaked timer
}, []);
```

## Me yasa tsafi ya zama mahimmanci

Ba tare da shi ba, kowa cirewa zai ƙara sabon agajiya/lajosawa kuma ba zai bugi tsohon ba - watacciyar ɓaraucin alaƙa. Lokaci-tsohon don `[dep]` tasuke: *aiki tasuke → (dogara canja) → aiki tsafi → aiki tasuke sake*.

**Gida:** kada amfani tasuke ga abubuwan kika iya lissafi a lokacin render (ƙadi ƙimomi maimakonsu), kuma wajen duk ƙimomi tasuke ta karantawa a tsarin dogara (aikin `react-hooks/exhaustive-deps` linti yana taimakawa).