Menene Promise kuma waɗanne jirage ake da shi?

Question

Accepted Answer

**Promise** shine wani abu da yake wakilta jiya wanda bazai saucy ba — sakamakon ƙarshen aiki na asynchronous. Yana da jirage guda uku:

- **pending** — farwa, bai gaida ba jiya.
- **fulfilled** — an gama cikin nasara (yana da jiya).
- **rejected** — kumsai (yana da dalilin/kuskure).

Da jiya ya gaida (fulfilled ko rejected) **immutable** ne — ba zai iya bada jiya ba.

```js
fetch("/api/user")
  .then(res => res.json())     // runs on fulfillment; return value flows down
  .then(user => render(user))
  .catch(err => showError(err)) // runs on ANY rejection in the chain
  .finally(() => hideSpinner()); // always runs
```

## Sarkar tana kunna asynchronous da aka kwara

Yada jiya da wa ba a gida cikin `.then` jiya zai jira kafin ya ci gaba, don haka ka guje karewa da zama da aka kwara ("callback hell"):

```js
getUser(id)
  .then(user => getPosts(user.id)) // returns a promise → chain waits for it
  .then(posts => console.log(posts));
```

## Masu aidatarwa don promises marasa iyali

```js
Promise.all([a, b, c]);     // wait for ALL; rejects fast if any fails
Promise.allSettled([a, b]); // wait for all, get each result/error
Promise.race([a, b]);       // settles with the FIRST to settle
Promise.any([a, b]);        // first to FULFILL (ignores rejections)
```

## Me ya sa yake mahimmanci

Promises ne jiya na asynchronous JS — sun kai nasara akan kwara da karewa, sun ba da warwarewa ta gida ta `.catch`, kuma `async/await` shine kawai suwaye mabudi a kan kansu.

Mantuwa da `.catch` (ƙin aminci da ba a jiye ba) sakamako ne da aka saba.