/**
 * Pure pattern masking utility functions.
 * Built-in presets: 'phone', 'ssn', 'credit-card', 'date-iso', or custom pattern string (e.g., '(###) ###-####')
 * Tokens:
 * '#' = digit (0-9)
 * 'A' = uppercase letter (A-Z)
 * 'a' = lowercase letter (a-z)
 * '*' = alphanumeric (0-9, A-Z, a-z)
 */
export interface MaskResult {
    masked: string;
    unmasked: string;
}
export declare function getPresetMask(preset: string): string;
export declare function applyMask(value: string, pattern: string): MaskResult;
export declare function unmaskValue(value: string, pattern: string): string;