/**
 * Converts a string to title case (capitalizes first letter of each word)
 * @param str - Input string
 * @param lowercaseRest - Whether to lowercase the rest of each word (default: true)
 * @returns String in title case
 * @example
 * toTitleCase("hello world") → "Hello World"
 * toTitleCase("hElLo wOrLd", false) → "HElLo WOrLd"
 */
export declare function toTitleCase(str: string, lowercaseRest?: boolean): string;
/**
 * Converts camelCase to snake_case
 * @param str - Input string in camelCase
 * @param uppercase - Whether to convert to UPPER_SNAKE_CASE (default: false)
 * @returns String in snake_case
 * @example
 * camelToSnake("myVarName") → "my_var_name"
 * camelToSnake("myVarName", true) → "MY_VAR_NAME"
 */
export declare function camelToSnake(str: string, uppercase?: boolean): string;
/**
 * Converts snake_case to camelCase
 * @param str - Input string in snake_case
 * @param pascal - Whether to convert to PascalCase (default: false)
 * @returns String in camelCase or PascalCase
 * @example
 * snakeToCamel("my_var_name") → "myVarName"
 * snakeToCamel("my_var_name", true) → "MyVarName"
 */
export declare function snakeToCamel(str: string, pascal?: boolean): string;
/**
 * Converts a string to a URL-friendly slug
 * @param str - Input string
 * @param separator - Character to use as separator (default: '-')
 * @param preserveCase - Whether to preserve original case (default: false)
 * @returns URL-friendly slug
 * @example
 * slugify("Hello World!") → "hello-world"
 * slugify("Hello World!", '_', true) → "Hello_World"
 */
export declare function slugify(str: string, separator?: string, preserveCase?: boolean): string;
/**
 * Truncates text with ellipsis
 * @param str - Input string
 * @param maxLength - Maximum length before truncation
 * @param ellipsis - Custom ellipsis string (default: '...')
 * @param preserveWords - Whether to preserve whole words (default: true)
 * @returns Truncated string
 * @example
 * truncateText("Hello world", 8) → "Hello..."
 * truncateText("Hello world", 8, '..', false) → "Hello wo.."
 */
export declare function truncateText(str: string, maxLength: number, ellipsis?: string, preserveWords?: boolean): string;
/**
 * Reverses a string.
 * @param str - Input string.
 * @returns Reversed string.
 */
export declare function reverseString(str: string): string;
/**
 * Counts words in a string (split by spaces).
 * @param str - Input string.
 * @returns Number of words.
 */
export declare function countWords(str: string): number;
/**
 * Checks if a string is a palindrome
 * @param str - Input string
 * @param caseSensitive - Whether comparison should be case-sensitive (default: false)
 * @param ignoreSpaces - Whether to ignore spaces (default: true)
 * @returns true if the string is a palindrome
 * @example
 * isPalindrome("Madam") → true
 * isPalindrome("A man a plan a canal Panama") → true
 * isPalindrome("Racecar", true) → false
 */
export declare function isPalindrome(str: string, caseSensitive?: boolean, ignoreSpaces?: boolean): boolean;
export declare function isEmail(str: string): boolean;
export declare function isURL(str: string): boolean;
/**
 * Trims extra spaces between words (e.g., "Hello   world" → "Hello world").
 * @param str - Input string.
 * @returns String with normalized spaces.
 */
export declare function trimExtraSpaces(str: string): string;
/**
 * Masks the local part of an email (e.g., "user@domain.com" → "us**@domain.com").
 * @param email - Email address.
 * @returns Masked email.
 * @throws Error if input is not a valid email.
 */
export declare function maskEmail(email: string): string;
/**
 * Generates a random string
 * @param length - Length of the string (default: 10)
 * @param options - Configuration options
 * @param options.includeNumbers - Whether to include numbers (default: true)
 * @param options.includeUppercase - Whether to include uppercase letters (default: true)
 * @param options.includeLowercase - Whether to include lowercase letters (default: true)
 * @param options.customChars - Custom character set to use
 * @returns Random string
 * @example
 * generateRandomString(8) → "A3b7GhK9"
 * generateRandomString(6, { includeNumbers: false }) → "aBcDef"
 */
export declare function generateRandomString(length?: number, options?: {
    includeNumbers?: boolean;
    includeUppercase?: boolean;
    includeLowercase?: boolean;
    customChars?: string;
}): string;