/**
 * Combines multiple ARIA ID references into a single space-separated string.
 * Filters out undefined, false, and empty string values.
 *
 * @param ids - Array of ID strings or falsy values
 * @returns Combined space-separated IDs or undefined if no valid IDs
 *
 * @example
 * combineIds('id1', 'id2', undefined) // 'id1 id2'
 * combineIds(undefined, false, '') // undefined
 * combineIds('id1', condition && 'id2') // 'id1' or 'id1 id2'
 */
export declare function combineIds(...ids: (string | undefined | false)[]): string | undefined;