/**
 * Converts a string to Title Case (each word capitalized, separated by spaces).
 * @param {string} string_ - Input string
 * @returns {string} Title Case string
 * @example
 * titleCase("hello world"); // "Hello World"
 * titleCase("a-quick brown_fox"); // "A Quick Brown Fox"
 */
export declare const titleCase: (string_: string) => string;