import { Observable } from 'rxjs';
/**
 * RxJS operator that unsubscribe from observables on destory.
 * Code forked from https://github.com/NetanelBasal/ngx-take-until-destroy
 *
 * IMPORTANT: Add the `untilDestroyed` operator as the last one to prevent leaks with intermediate observables in the
 * operator chain.
 *
 * @param instance The parent Angular component or object instance.
 * @param destroyMethodName The method to hook on (default: 'ngOnDestroy').
 * @example
 * ```
 * import { untilDestroyed } from '@app/core';
 *
 * @Component({
 * selector: 'app-example',
 *   templateUrl: './example.component.html'
 * })
 * export class ExampleComponent implements OnInit, OnDestroy {
 *   ngOnInit() {
 *     interval(1000)
 *       .pipe(untilDestroyed(this))
 *       .subscribe(val => console.log(val));
 *   }
 *
 *   // This method must be present, even if empty.
 *   ngOnDestroy() {
 *     // To protect you, an error will be thrown if it doesn't exist.
 *   }
 * }
 * ```
 */
export declare function untilDestroyed(instance: object, destroyMethodName?: string): <T>(source: Observable<T>) => Observable<T>;