/**
 * Helper for enumerating a type from a const object
 * Example: export type Foo = ValuesOf\<typeof Foo\>
 * @public
 */
export type ValuesOf<T> = T[keyof T];
/**
 * Creates a type guard that checks if a node is a custom element whose tag name ends with the given suffix.
 *
 * @param tagSuffix - The tag name suffix to match (e.g., '-dropdown', '-option').
 * @returns A predicate function that narrows the node to the specified element type.
 * @public
 */
export declare function isCustomElement<T extends HTMLElement>(tagSuffix: string): (element?: Node | null) => element is T;
/**
 * A test that ensures that all arguments are HTML Elements
 */
export declare function isHTMLElement(...args: any[]): boolean;