/**
 * Converts a string to PascalCase.
 *
 * Removes non-alphanumeric characters, splits on casing and digits,
 * capitalizes each word, and strips leading/trailing separators.
 *
 * @example
 * ```ts
 * toPascalCase("hello world"); // "HelloWorld"
 * ```
 *
 * @example
 * ```ts
 * toPascalCase("first_name"); // "FirstName"
 * ```
 *
 * @example
 * ```ts
 * toPascalCase("user42Profile"); // "User42Profile"
 * ```
 *
 * @example
 * ```ts
 * toPascalCase("API response code"); // "ApiResponseCode"
 * ```
 *
 * @example
 * ```ts
 * toPascalCase("  messy__input--string  "); // "MessyInputString"
 * ```
 *
 * @param input A string to be returned in PascalCase.
 * @returns The PascalCased version of the input string.
 */
export declare function toPascalCase(input: string): string;