Javascript debounce shim

debounce.js

/**
 * Make sure that we can't accidentally iterate over custom methods
 * @param {Object} proto
 * @param {string} fName
 * @param {function(?)} fn
 */
function defineProperty(proto, fName, fn) {
	if (!proto[fName]) {
		proto[fName] = fn;
		(Object.defineProperty || $.noop)(proto, fName, {"enumerable": false});
	}
}

/**
 * Debounce a function, preventing it from being called too often
 * @method debounce
 * @for Function
 * @param {number} [timer] Number of ms to debounce by
 * @param {boolean} [wait] Call after delay, otherwise call immediately and don't re-call
 */
defineProperty(FunctionPrototype, "debounce", function(timer, wait) {
	var func = this, timeout;

	return function() {
		var obj = this, args = arguments;
		function delayed() {
			if (wait) {
				func.apply(obj, args);
			}
			timeout = null;
		}
		if (timeout) {
			clearTimeout(timeout);
		} else if (!wait) {
			func.apply(obj, args);
		}
		timeout = setTimeout(delayed, timer || 100);
	};
});