Menene resolvers? Bayyana resolver chain da arguments ɗinsa.

Question

IT Interview Practice · Accepted Answer

**Resolver** wani aiki ne (function) da yake samar da ƙima ga fili guda ɗaya a cikin schema. GraphQL yana tafiya cikin tambayar fili-bayan-fili kuma yana kiran resolver da ya dace da kowanne — wannan tafiyar ita ce **resolver chain**.

## Arguments guda huɗu na resolver

Kowane resolver yana karɓar `(parent, args, context, info)`:

- **parent** — ƙimar da resolver na matakin sama ya mayar (misali object ɗin `User` lokacin da ake warware `user.posts`).
- **args** — arguments na filin daga tambayar (`{ id: "1" }`).
- **context** — object na kowace buƙata da dukkan resolvers suke rabawa; yana riƙe da bayanan auth, DB client, da loaders.
- **info** — AST da bayanan aiwatarwa (ba a cika buƙatarsa ba).

```js
const resolvers = {
  Query: {
    // top-level: parent is undefined; read args, use context for data access
    user: (_parent, args, ctx) => ctx.db.users.findById(args.id),
  },
  User: {
    // runs for EACH user; parent is the resolved user object
    posts: (parent, _args, ctx) => ctx.db.posts.findByAuthor(parent.id),
    // no resolver needed for 'name' -> the default resolver reads parent.name
  },
};
```

In wani fili ba shi da resolver bayyananne, GraphQL yana amfani da **default resolver** wanda kawai yake karanta `parent[fieldName]`. Wannan ne dalilin da ya sa scalar fields a kan wani object mai sauƙi galibi ba sa buƙatar wani code.

## Me ya sa yake da muhimmanci

Fahimtar cewa resolvers suna gudana **kowane fili, daga sama zuwa ƙasa, suna bin resolver chain na parent** yana bayyana duka yadda ake haɗa bayanan nested da kuma dalilin da ya sa nested resolvers marasa hankali suke haddasa matsalar N+1 — tambayar hira ta biye da haka.

Arguments guda huɗu na resolver

Me ya sa yake da muhimmanci

Tambayoyi masu alaƙa