Mousemove Optimized

mousemove.js

var last_known_scroll_position = 0;
var ticking = false;

function doSomething(scroll_pos) {
  // do something with the scroll position
}

window.addEventListener('mousemove', function(e) {

  last_known_position = {
    x: e.clientX,
    y: e.clientY
  };

  if (!ticking) {
    window.requestAnimationFrame(function() {
      doSomething(last_known_position);
      ticking = false;
    });
     
    ticking = true;

  }
  
});