Toggling document touchmove on/off by adding / removing EventListener

Question

I have a request to implement a lock/unlock function for body scrolling on mobile as follows :

var myObj = {
 disableBodyScroll: function() {
    document.querySelector('body').addEventListener("touchmove", function(e) {
      e.preventDefault();
      return false;
    }, 
    {passive: false}
    ); 
  },
  enableBodyScroll: function() {
    document.querySelector('body').removeEventListener("touchmove", function(e) {
      e.preventDefault();
      return false;
    }, 
    {passive: false}
    ); 
  }
}

when I do myObj.disableBodyScroll() it works fine. but myObj.enableBodyScroll() it doesn't and my scroll stays locked...

Any possible reason for this?

ref : https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener

Answer 1

I think it's because you don't pass the same listener function. Your enable and disable functions create both a new eventListener function. So the removeEventListener can't find the eventListener reference

Try this :

var myObj = {
        handleTouchMove: function (e) {
            e.preventDefault();
            return false;
        },
        disableBodyScroll: function() {
            document.querySelector('body').addEventListener("touchmove", myObj.handleTouchMove, {passive: false}
            );
        },
        enableBodyScroll: function() {
            document.querySelector('body').removeEventListener("touchmove", myObj.handleTouchMove, {passive: false}
            );
        }
    }