/**
 * @typedef {object} UniqueSet
 * @property {Function} addItem Adds items to the priority set.
 * @property {Function} getItems Gets items from the set in order of addition.
 */
/**
 * Creates a new unique set.
 *
 * @param {object} config The config for priority set.
 * @param {Function} config.errorItemExists The function to generate custom error message if item is already in the set.
 * @returns {UniqueSet}
 */
export declare function createUniqueSet({ errorItemExists }?: {
    errorItemExists?: Function;
}): {
    addItem: (item: unknown) => void;
    clear: () => void;
    getItems: () => unknown[];
};