Grouped throttle function

groupedThrottle.js

function throttleGroup(fn, count, delay) {
	let queue = [];
	let nextDrain = null;
	
	function scheduleDrain() {
		nextDrain = window.setTimeout(drainQueue, delay);
	}
	
	function drainQueue() {
		const groupSize = Math.min(count, queue.length);
		for (let i = 0; i < groupSize; i++) {
			fn.apply(this, ...queue.shift())
		}
		nextDrain = null;
		if (queue.length) {
			scheduleDrain();
		}
	}
	
	return function(...args) {
		queue.push([args]);
		if (!nextDrain) {
			scheduleDrain();
		}
	}
}

function sayer(a) {
  console.log(a, new Date().toLocaleString())
}

function manySayer() {
	const throttledSayer = throttleGroup(sayer, 2, 1000);
	for (let i = 0; i < 30; i++) {
		throttledSayer('Hello world! ' + i);
	}
}

manySayer();