import { OpaqueToken } from '@angular/core';
export declare const LIVE_ANNOUNCER_ELEMENT_TOKEN: OpaqueToken;
/** Possible politeness levels. */
export declare type AriaLivePoliteness = 'off' | 'polite' | 'assertive';
export declare class LiveAnnouncer {
    private _liveElement;
    constructor(elementToken: any);
    /**
     * Announces a message to screenreaders.
     * @param message Message to be announced to the screenreader
     * @param politeness The politeness of the announcer element
     */
    announce(message: string, politeness?: AriaLivePoliteness): void;
    /** Removes the aria-live element from the DOM. */
    _removeLiveElement(): void;
    private _createLiveElement();
}