Responive Menu with swipe gesture

responsiveMenuWithGesture.js

let body =  document.querySelector("body");
let sidenav =  document.querySelector(".side-nav");

function openNav() {
	sidenav.style.transform = "translateX(250px)";
	body.style.transform = "translateX(-250px)"; 
	body.style.backgroundColor = "rgba(0,0,0,0.4)";
}

function closeNav() {
	sidenav.style.transform = "translateX(250px)";
	body.style.transform = "translateX(0px)";
	body.style.backgroundColor = "white";
}

var touchstartX = 0,
    touchstartY = 0,
    touchendX   = 0,
    touchendY   = 0;

body.addEventListener('touchstart', function(e) {
	touchstartX = e.changedTouches[0].screenX;
	touchstartY = e.changedTouches[0].screenY;
}, false);

body.addEventListener('touchend', function(e) {
 	touchendX = e.changedTouches[0].screenX;
  touchendY = e.changedTouches[0].screenY;
	handleGesure();
}, false); 

function handleGesure() {
		if ((touchendX + 80) < touchstartX) {
        openNav();
    }
		if (touchendX > (touchstartX + 80)) {
				closeNav();
    }
}