export declare function cs(str: string): string;
export declare function addClass(child: React.ReactNode, newClass: string): string | number | bigint | boolean | Iterable<import("react").ReactNode> | Promise<string | number | bigint | boolean | import("react").ReactPortal | import("react").ReactElement<unknown, string | import("react").JSXElementConstructor<any>> | Iterable<import("react").ReactNode>> | import("react").DetailedReactHTMLElement<unknown, HTMLElement>;