interface UsernameValidationOptions {
    minLength?: number;
    maxLength?: number;
    allowSpaces?: boolean;
    allowDashes?: boolean;
    allowUnderscores?: boolean;
    allowPeriods?: boolean;
    noLeadingTrailingSpecialChars?: boolean;
    noConsecutiveSpecialChars?: boolean;
    blacklist?: string[];
}
interface UsernameValidationResult {
    valid: boolean;
    errors: string[];
}
declare function isUsername(username: string, options?: UsernameValidationOptions): UsernameValidationResult;

export { type UsernameValidationOptions, type UsernameValidationResult, isUsername };