import * as i0 from "@angular/core";
/**
 * A service to track the currently active theme.
 *
 * @internal
 * @group Services
 */
export declare class ThemeTrackingService {
    #private;
    /**
     * The observable that emits the current theme, shared among subscribers.
     * This observable prevents emitting the same value twice in a row.
     * It also updates the private #currentTheme property.
     */
    readonly currentTheme$: import("rxjs").Observable<string | null>;
    /**
     * Set the current theme.
     *
     * @param {string | null} arg
     */
    set currentTheme(arg: string | null);
    /**
     * Get the current theme.
     *
     * @returns {string | null} The current theme
     */
    get currentTheme(): string | null;
    static ɵfac: i0.ɵɵFactoryDeclaration<ThemeTrackingService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<ThemeTrackingService>;
}