Calculate Scrollbar Width

calc-scrollbar-width.js

function calcScrollbarWidth() {
  const outerDiv = document.createElement('div');
  const innerDiv = document.createElement('div');
  outerDiv.style.overflow = 'scroll';
  document.body.insertBefore(outerDiv, null);
  outerDiv.insertBefore(innerDiv, null);
  window.scrollbarWidth = outerDiv.offsetWidth - innerDiv.offsetWidth;
  outerDiv.removeChild(innerDiv);
  document.body.removeChild(outerDiv);
}