Log only on programmer's day

programmers-day.js

/**
 * Get current day number of the given date.
 *
 * @param now Target date (current date by default).
 */
const dayNumber = (now = new Date()) =>
	Math.floor(
		(now.getTime() - new Date(now.getFullYear(), 0, 0).getTime()) / 864e5,
	);

// Usage:

const diff = 256 - dayNumber();

console.log(
	`${
		diff === 0
			? "It's international"
			: `${diff} days ${diff > 0 ? `until` : `ago it was`}`
	} programmer's day!`,
);