/**
 * Returns a Set-like view of the given array.
 *
 * For plain arrays, the set interface is backed by the array,
 * ensuring values appear only once. For observable arrays, mutations
 * are wrapped in actions using MobX.
 *
 * @template T The type of the values.
 * @param data An array to be wrapped as a Set.
 * @returns A Set-like view over the array.
 * @throws When data is not an array.
 */
export declare function asSet<T>(data: T[]): Set<T>;