export declare function isSpace(str: string): boolean;
export declare function isDigit(str: string): boolean;
export declare function isAlpha(str: string): boolean;
export declare function connect(strings: string[]): string;
export declare function findGroupEnd(text: string, startIndex?: number): number;
export declare function searchFrom(text: string, target: string | RegExp, startIndex?: number, endIndex?: number): number;