/**
 * Converts a string to camelCase.
 * Removes all non-alphanumeric separators and capitalizes each word except the first.
 *
 * @example
 * ```ts
 * toCamelCase("hello world"); // "helloWorld"
 * ```
 *
 * @example
 * ```ts
 * toCamelCase("Hello_world"); // "helloWorld"
 * ```
 *
 * @example
 * ```ts
 * toCamelCase("API_response_code"); // "apiResponseCode"
 * ```
 *
 * @example
 * ```ts
 * toCamelCase("user-42-profile"); // "user42Profile"
 * ```
 *
 * @example
 * ```ts
 * toCamelCase("ThisIsALongVariableName"); // "thisIsALongVariableName"
 * ```
 *
 * @param input The input string to be camelized.
 * @returns The camelCased version of the input string.
 */
export declare function toCamelCase(input: string): string;