Measure width and height of an unrendered HTML element.

measure.js

/**
 * Measure an element.
 *
 * @param  {HTMLElement} element      - The element.
 * @param  {HTMLElement} [parentNode] - The parent element.
 * @return {Object}
 */
function measure(element, parentNode) {
  parentNode = parentNode || document.body;
  element.style.display = 'block';
  element.style.visibility = 'hidden';
  element.style.zIndex = -1;
  parentNode.appendChild(element);
  const {
    clientWidth,
    clientHeight,
    offsetWidth,
    offsetHeight,
    scrollWidth,
    scrollHeight,
  } = element;
  parentNode.removeChild(element);
  return {
    clientWidth,
    clientHeight,
    offsetWidth,
    offsetHeight,
    scrollWidth,
    scrollHeight,
  };
}