/**
 * Safely validates a regex pattern for potential ReDoS vulnerabilities.
 * Checks for dangerous patterns that could cause exponential backtracking.
 *
 * @param {string} pattern - The regex pattern to validate
 * @returns {boolean} True if pattern is safe, false if potentially dangerous
 *
 * @example
 * isRegexSafe("^[a-z]+$")    // returns true (safe pattern)
 * isRegexSafe("(a+)+")       // returns false (nested quantifiers)
 * isRegexSafe("(a|aa)+")     // returns false (overlapping alternation)
 */
export declare const isRegexSafe: (pattern: string) => boolean;
