/**
 * Safely formats a number using the Intl.NumberFormat API.
 *
 * @param val - The value to be formatted.
 * @param locales - A string with a BCP 47 language tag, or an array of such strings.
 * @param options - An options object that defines the formatting options.
 * @returns The formatted number as a string, or the input value if formatting fails.
 *
 * @example
 * // Example 1: When the value is a number
 * const result1 = numberFormat(123456.789);
 * // Result: "123,456.789"
 *
 * // Example 2: When the value is a string
 * const result2 = numberFormat("123456.789");
 * // Result: "123,456.789"
 *
 * // Example 3: When the value is a string representing a number
 * const result3 = numberFormat("123456.789");
 * // Result: "123,456.789"
 */
export declare function numberFormat(val: unknown, locales?: Intl.LocalesArgument, options?: Intl.NumberFormatOptions): string;