javascript debounce

debounce.js

/**
 * Debounce creates a FUNCTION that when invoked, delays invoking fn for wait milliseconds since
 * the last time it is called.
 *
 * @param {number} fn - function to call
 * @param {number} wait - duration in milliseconds
 * @param {number} maxWait - max duration in milliseconds before calling {@param fn}
 * @retun {function} a function that will wait {@param wait} milliseconds since it's last called to invoke {@param fn}.
 */
function debounce(fn, wait, maxWait=null) {
	var timeoutId = null,
		timeoutIdMax = null;

	return function() {
		var context = this, args = arguments;
		if (timeoutId!==null) {
			window.clearTimeout(timeoutId);
		}
		if (maxWait!==null && timeoutIdMax===null) {
			timeoutIdMax = window.setTimeout(function () {
				window.clearTimeout(timeoutId);
				timeoutId = timeoutIdMax = null;
				fn.apply(context, args);
			}, maxWait); // you want to make sure foo executes and timeoutId is cancelled
		}

		timeoutId = window.setTimeout(function() {
			window.clearTimeout(timeoutId);
			timeoutId = null;

			fn.apply(context, args);

			if (maxWait!==null && timeoutIdMax!==null){
				window.clearTimeout(timeoutIdMax);
				timeoutIdMax = null;
			}
		}, wait); // you want to make sure foo executes maxTimeoutId is cancelled
	};
}