Aiki shine ajin ilimin da ba na UI — karfe jingina, ka'idodi kasua, jilar hannu mai amfani, kada — wanda sassa za su iya sake amfani da shi. Dependency Injection (DI) shine yadda Angular ba waɗannan aiki ga sassa waɗanda suke buƙatansu, maimakon sassa su haifar da su da kansu.
{ } ;
({ : })
{
users = [];
() { .; }
() { ..(u); }
}
Kaɗan @Injectable({ providedIn: "root" }) yana kumatawa da aiki ga tsarin DI na Angular azaman gida daya mai amfani (singleton) gidan baba duka.
@Component({ ... })
export class UserListComponent {
// Angular sees this constructor param and INJECTS the singleton automatically
constructor(private userService: UserService) {}
users = this.userService.getUsers(); // just use it
}
Kai kawai ka bayyana aiki azaman siga-halaye shigar halaye; DI na Angular haifa da baba misalin. Ba ka taba rubuta new UserService(). (Angular na zamani kuma zai iya amfani da aikin inject() maimakon shigar halaye na gida.)
import { inject } from "@angular/core";
export class UserListComponent {
private userService = inject(UserService); // alternative injection style
}
✓ Single source of truth — one shared UserService instance across components
✓ Loose coupling — components depend on the type, not on constructing it
✓ Testability — swap in a mock service in tests easily
✓ Lifecycle management — Angular handles creation and sharing
Saboda sassa bai haifar da dogaro takwas, za ka iya yanke aiki wayo a gwajin, ko canja aiki gida duka a wuri gida daya.
Aiki + DI suna tsakiyar Angular gida: sassa suna kasance a baje jiya a kan UI daidai da aiki da jilar hannu, da DI yana haɗa su tare da ɗan kaɗan dangantaka.
Wannan rabuwa (da gwajawa da yake kawo da shi) shine daya daga cikin fahimta na Angular — da aka karbe daga tsarin baja — da @Injectable({ providedIn: 'root' }) shine sagi na jiya na gida, mai bayyanwa, singleton mai amfani.