throttle

throttle returns a wrapper that runs fn at most once per limit milliseconds. Unlike debounce, calls during the cooldown are dropped rather than deferred — so the first call in a burst wins instead of the last.

export function throttle<T extends (...args: unknown[]) => void>(
	fn: T,
	limit: number,
): (...args: Parameters<T>) => void {
	let lastCall = -Infinity;
	return (...args: Parameters<T>) => {
		const now = Date.now();
		if (now - lastCall >= limit) {
			lastCall = now;
			fn(...args);
		}
	};
}

When to reach for it

• Scroll-position trackers that only need to update every ~100ms.
• High-frequency mousemove handlers driving cheap visual updates.
• Rate-limiting analytics events from rapid user interactions.