Tap listener

utils.js

window.utils = (function() {

	function touch(el, type, listener) {
		if (type === 'tap') {
			var isDragging, startPos;

			function touchStart(e) {
				el.addEventListener('touchmove', touchMove);
				el.addEventListener('touchend', touchEnd);
				isDragging = false;
				startPos = [e.touches[0].screenX, e.touches[0].screenY];
			}

			function touchMove(e) {
				var movePos = [e.touches[0].screenX, e.touches[0].screenY],
					distanceX = Math.abs(startPos[0] - movePos[0]),
					distanceY = Math.abs(startPos[1] - movePos[1]),
					distance = parseInt(Math.sqrt(Math.pow(distanceX, 2) + Math.pow(distanceY, 2)), 10);

				if (distance > 15) {
					isDragging = true;
				}
			}

			function touchEnd(e) {
				el.removeEventListener('touchmove', touchMove);
				el.removeEventListener('touchend', touchEnd);
				if (!isDragging && listener) {
					listener(e);
				}
			}

			el.addEventListener('touchstart', touchStart);
		}
	}

	function closest(el, selector) {
		while (el) {
			if (el.webkitMatchesSelector(selector)) {
				return el;
			}
			el = el.parentElement;
		}
	}

	/* export API */
	return {
		touch: touch,
		closest: closest
	};

}());