misskey/packages/frontend/src/scripts/confetti.ts

import _confetti from 'canvas-confetti';
import * as os from '@/os';

export function confetti(options: { duration?: number; } = {}) {
	const duration = options.duration ?? 1000 * 4;
	const animationEnd = Date.now() + duration;
	const defaults = { startVelocity: 30, spread: 360, ticks: 60, zIndex: os.claimZIndex('high') };

	function randomInRange(min, max) {
		return Math.random() * (max - min) + min;
	}

	const interval = setInterval(() => {
		const timeLeft = animationEnd - Date.now();

		if (timeLeft <= 0) {
			return clearInterval(interval);
		}

		const particleCount = 50 * (timeLeft / duration);
		// since particles fall down, start a bit higher than random
		_confetti(Object.assign({}, defaults, { particleCount, origin: { x: randomInRange(0.1, 0.3), y: Math.random() - 0.2 } }));
		_confetti(Object.assign({}, defaults, { particleCount, origin: { x: randomInRange(0.7, 0.9), y: Math.random() - 0.2 } }));
	}, 250);
}