/**
 * Removes duplicate objects from an array based on their `key` property.
 *
 * @template T - The type of objects in the array. Must include a `key` property.
 * @param {T[]} items - The array of objects to deduplicate.
 * @returns {T[]} A new array containing only the first occurrence of each unique `key`.
 */
export declare const deduplicateByKey: <T extends {
    key: any;
}>(items: T[]) => T[];