export declare class StringUtil { static isEmpty(str: string | undefined | null): boolean; static uint8ArrayToString(array: Uint8Array): string; static stringToUint8Array(str: string): Uint8Array; static base64Uint8Array(content: Uint8Array): string; static base64String(content: string): string; static debase64ToUint8Array(content: Uint8Array | string): Uint8Array; static debase64String(content: string): string; static isIdCardNumberValid(t23?: string): boolean; static genOssFileName(prefix: string, type: string, r23: string): string; static getHexColorWithOpacity(color: string, alpha: number): string; static s10(color: string): boolean; static t10(alpha: string): boolean; static localHashString(str: string): number; } 