import { Injector } from '@angular/core';
import { Observable } from 'rxjs';
import type { LazyImportLoaderFn } from './inject-lazy-impl';
/**
 * Loads a service lazily. The service is loaded when the observable is subscribed to.
 *
 * @param loader A function that returns a promise of the service to load.
 * @param injector The injector to use to load the service. If not provided, the current injector is used.
 * @returns An observable of the service.
 *
 * @example
 * ```ts
 * const dataService$ = injectLazy(() => import('./data-service').then((m) => m.MyService));
 * or
 * const dataService$ = injectLazy(() => import('./data-service'));
 * ```
 */
export declare function injectLazy<T>(loader: LazyImportLoaderFn<T>, injector?: Injector): Observable<T>;