/**-----------------------------------------------------------------------------------------
* Copyright © 2025 Progress Software Corporation. All rights reserved.
* Licensed under commercial license. See LICENSE.md in the project root for more information
*-------------------------------------------------------------------------------------------*/
/**
 * @hidden
 *
 * Quick look-up structure for combinations of keys.
 * Similar to the native JS Set, however, working with a couple of keys instead of with a single key.
 * Supports both primitive keys and object keys (compared by reference).
 */
export declare class PairSet {
    /**
     * Gets the total number of X/Y key pairs.
     */
    get size(): number;
    /**
     * Holds a set of Y keys for each defined X key.
     * Each X key creates a map which holds a set of Y keys.
     *
     * Map { 1 => Set { 1, 2, 3 } } // pairs: [1, 1], [1, 2], [1, 3]
     */
    private keysX;
    /**
     * Count the each added or deleted key manually to avoid iterating over all items when calling `this.size`.
     */
    private totalKeysCount;
    constructor(items?: any[], keyXField?: string, keyYField?: string);
    /**
     * Adds a couple of items identified as a combination.
     */
    add(keyX: any, keyY: any): void;
    /**
     * Adds a combination of a couple of items identified together.
     */
    delete(keyX: any, keyY: any): void;
    /**
     * Checks whether the defined combination is stored.
     */
    has(keyX: any, keyY: any): boolean;
    /**
     * Clears all key combinations.
     */
    clear(): void;
    /**
     * Converts the persisted data structure to an array of objects,
     * using the provided field names for the object props.
     */
    toArray(keyXField: string, keyYField: string): any[];
}