How do I create a vertical scroll mousewheel function (jQuery)?

I’ve created this script:

jQuery(".resultlist").mousewheel(function(event, delta) {
  this.scrollLeft -= (delta);
  event.preventDefault();
});

which fires a horizontal scroll function over the .resultlist container and this is working as expected. I need to disable this on screen widths underneath 545px so I’ve wrapped it in a resize function.

/* Trigger Resize Script */
jQuery(document).ready(function(){
    function resizeForm(){
        var width = (window.innerWidth > 0) ? window.innerWidth : document.documentElement.clientWidth;
        if(width > 545){
            jQuery(".resultlist").mousewheel(function(event, delta) {
              this.scrollLeft -= (delta);
              event.preventDefault();
            });
        } else {
            // invert
        }    
    }
    window.onresize = resizeForm;
    resizeForm();
});
/* End Trigger Resize Script */

The problem I have is that the script still runs if else is true, I did start working on a function that would include and then delete a separate script based on screenwidth but this became very cumbersome and is surely not the right way to achieve this.

I need to convert the mousewheel function so that it behaves like a normal vertical scroll instead, so that I can switch between my current horizontal scroll and a normal vertical scroll inside the resize function.

How do I amend the below function to scroll vertically?

jQuery(".resultlist").mousewheel(function(event, delta) {
   this.scrollLeft -= (delta);
   event.preventDefault();
});