import { OnDestroy } from '@angular/core';
import { Platform } from '@angular/cdk/platform';
import * as i0 from "@angular/core";
/**
 * Interface used to register message elements and keep a count of how many registrations have
 * the same message and the reference to the message element used for the `aria-describedby`.
 */
export interface RegisteredMessage {
    /** The element containing the message. */
    messageElement: Element;
    /** The number of elements that reference this message element via `aria-describedby`. */
    referenceCount: number;
}
/**
 * ID used for the body container where all messages are appended.
 * @deprecated No longer being used. To be removed.
 * @breaking-change 14.0.0
 */
export declare const MESSAGES_CONTAINER_ID = "cdk-describedby-message-container";
/**
 * ID prefix used for each created message element.
 * @deprecated To be turned into a private variable.
 * @breaking-change 14.0.0
 */
export declare const CDK_DESCRIBEDBY_ID_PREFIX = "cdk-describedby-message";
/**
 * Attribute given to each host element that is described by a message element.
 * @deprecated To be turned into a private variable.
 * @breaking-change 14.0.0
 */
export declare const CDK_DESCRIBEDBY_HOST_ATTRIBUTE = "cdk-describedby-host";
/**
 * Utility that creates visually hidden elements with a message content. Useful for elements that
 * want to use aria-describedby to further describe themselves without adding additional visual
 * content.
 */
export declare class AriaDescriber implements OnDestroy {
    /**
     * @deprecated To be turned into a required parameter.
     * @breaking-change 14.0.0
     */
    private _platform?;
    private _document;
    /** Map of all registered message elements that have been placed into the document. */
    private _messageRegistry;
    /** Container for all registered messages. */
    private _messagesContainer;
    /** Unique ID for the service. */
    private readonly _id;
    constructor(_document: any, 
    /**
     * @deprecated To be turned into a required parameter.
     * @breaking-change 14.0.0
     */
    _platform?: Platform | undefined);
    /**
     * Adds to the host element an aria-describedby reference to a hidden element that contains
     * the message. If the same message has already been registered, then it will reuse the created
     * message element.
     */
    describe(hostElement: Element, message: string, role?: string): void;
    /**
     * Adds to the host element an aria-describedby reference to an already-existing message element.
     */
    describe(hostElement: Element, message: HTMLElement): void;
    /** Removes the host element's aria-describedby reference to the message. */
    removeDescription(hostElement: Element, message: string, role?: string): void;
    /** Removes the host element's aria-describedby reference to the message element. */
    removeDescription(hostElement: Element, message: HTMLElement): void;
    /** Unregisters all created message elements and removes the message container. */
    ngOnDestroy(): void;
    /**
     * Creates a new element in the visually hidden message container element with the message
     * as its content and adds it to the message registry.
     */
    private _createMessageElement;
    /** Deletes the message element from the global messages container. */
    private _deleteMessageElement;
    /** Creates the global container for all aria-describedby messages. */
    private _createMessagesContainer;
    /** Removes all cdk-describedby messages that are hosted through the element. */
    private _removeCdkDescribedByReferenceIds;
    /**
     * Adds a message reference to the element using aria-describedby and increments the registered
     * message's reference count.
     */
    private _addMessageReference;
    /**
     * Removes a message reference from the element using aria-describedby
     * and decrements the registered message's reference count.
     */
    private _removeMessageReference;
    /** Returns true if the element has been described by the provided message ID. */
    private _isElementDescribedByMessage;
    /** Determines whether a message can be described on a particular element. */
    private _canBeDescribed;
    /** Checks whether a node is an Element node. */
    private _isElementNode;
    static ɵfac: i0.ɵɵFactoryDeclaration<AriaDescriber, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<AriaDescriber>;
}