Inject Destroy

inject-destroy.ts

import { DestroyRef, inject } from '@angular/core';
import { ReplaySubject } from 'rxjs';

/**
 * Injects the `DestroyRef` service and returns a `ReplaySubject` that emits
 * when the component is destroyed.
 *
 * @throws {Error} If no `DestroyRef` is found.
 * @returns {ReplaySubject<void>} A `ReplaySubject` that emits when the component is destroyed.
 *
 * @example
 * // In your component:
 * export class MyComponent {
 *   private destroy$ = injectDestroy();
 *
 *   getData() {
 *     return this.service.getData()
 *       .pipe(takeUntil(this.destroy$))
 *       .subscribe(data => { ... });
 *   }
 * }
 */
export const injectDestroy = () => {
  const destroyRef = inject(DestroyRef, { optional: true });

  if (!destroyRef) throw new Error('No DestroyRef found');

  const subject$ = new ReplaySubject<void>(1);

  destroyRef.onDestroy(() => {
    subject$.next();
    subject$.complete();
  });

  return subject$;
};