import type { DirectiveLevel } from './types.js';
/**
 * Get the regular expression pattern for matching directives based on
 * `level` and `marker`.
 */
export declare function getDirectivePattern(level: DirectiveLevel, marker: string): string;
/**
 * Convert the first character of a string to uppercase.
 */
export declare function ucFirst(str: string): string;
/**
 * Check if a given HTML tag is a void element.
 */
export declare function isVoidElements(str: string): boolean;