import { RefObject } from 'react';
/**
 * When `uploadStrategy="custom"` and the upload is marked `required`, the
 * native `required` attribute can't do the work (the input isn't posted).
 * This hook attaches a submit listener to the containing `<form>` that
 * prevents submission if the queue is empty, and surfaces a validation
 * error via `onMissingFiles`.
 *
 * Passive in `form` strategy — native validation handles that case.
 */
export declare const useRequiredFormValidation: (fileInputRef: RefObject<HTMLInputElement | null>, { uploadStrategy, required, currentFileCount, onMissingFiles, }: {
    uploadStrategy: "form" | "custom";
    required: boolean;
    currentFileCount: number;
    onMissingFiles: () => void;
}) => void;