export interface FileToBase64UrlOptions {
    onprogress?: (evt: ProgressEvent<FileReader>) => void;
    onWarning?: (message: string, error: any) => void;
}
/**
 * Converts `file` to a base64 data URL.
 */
declare const fileToBase64Url: (file: Blob, options?: FileToBase64UrlOptions) => Promise<string | null>;
export default fileToBase64Url;