/**
 * Formats a number with leading zeros so the resulting string is 4 digits long.
 * Similar to `string.padStart(4, '0')` but will also format
 * negative numbers similar to how the JavaScript date formats
 * negative year numbers (e.g. `-37` is formatted as `-000037`).
 */
export declare function pad4(num: number): string;
/**
 * Formats a number with leading zeros so the resulting string is 2 digits long.
 * Similar to `string.padStart(2, '0')`.
 */
export declare function pad2(num: number): string;