A cikin NestJS, mai samarwa shine aji daya da zai iya zama ingantawa azaman dogara, kuma aiki shine nau'i mafi yawan — aji mai jiya aikin kasuwanci. Sarkakkin aji tare da @Injectable() yana kaiwa mai samarwa wanda tsarin DI na NestJS zai iya tsara da inganta.
import { Injectable } from "@nestjs/common";
@Injectable() // marks the class as a provider (injectable)
export class UsersService {
private users = [];
findAll() { return this.users; } // business logic
findOne(id: string) { return this.users.find(u => u.id === id); }
create(data) { this.users.push(data); return data; }
}
Fasalliyar @Injectable() tana gaya wa NestJS cewa ajin nan yana cikin jujjuyawar dogara — zai iya zama ingantawa cikin masu sarrafawa ko sauran masu samarwa.
@Controller("users")
export class UsersController {
// NestJS sees this parameter and INJECTS a UsersService instance automatically
constructor(private usersService: UsersService) {}
@Get()
findAll() {
return this.usersService.findAll(); // use the injected service
}
}
Kuna bayanin dogara azaman sigar gida na m ganin; NestJS yana tsara da samarwa — ba za ku rubuta new UsersService() ba.
@Module({
controllers: [UsersController],
providers: [UsersService], // register the provider so DI can resolve it
exports: [UsersService], // make it available to OTHER modules that import this one
})
export class UsersModule {}
Dole ne a jigilar masu samarwa a cikin providers array na module domin DI sanin su, kuma exports yana bayarwa tare da wasu modules.
By default, NestJS creates ONE shared instance of each provider (singleton scope)
for the whole application → efficient, shared state.
(Other scopes exist: REQUEST-scoped, TRANSIENT — but singleton is the default.)
Controller → handles HTTP (routing, request/response)
Service → handles business logic (rules, data access, computations)
→ Separation makes logic REUSABLE (multiple controllers can use one service),
TESTABLE (test the service in isolation), and ORGANIZED.
Masu samarwa da aiki su ne tsari na gida na architecture ta NestJS da kuma tsarinsa na dogara-tashe.
Aiki yana riƙe da aikin kasuwanci na aikace-aikace, ɓanante daga masu sarrafawa (wanda ke juyawa ƈaware HTTP kawai) — raban aini na hankali ya fara ikonka da bata-taba cikin masu sarrafawa, ƈawa sannan a ɗagadda, kuma daidai-daidai.
Ganin cewa @Injectable() yana buɗe aji azaman mai samarwa mai ƈo, cewa masu samarwa suna a jigilinta a modules kuma suna ingantawa ta dariƒa na m ganin (DI yana tsara gwajin don ku), kuma su ne singletons ta tawada, su ne ilimin asali na rai maa NestJS.
Rashin mai samarwa/aiki, tare da masu sarrafawa da modules, shine m goda ga kowane aikace-aikace na NestJS — amfanai shi su sanya ƙara, gajiya kumoleya da dukƙa — kuma shi ne cikin farko damibagun tunawa na tsarin hankali.