Locks scrollbars starting from an element

lockScroll.js

/**
 * Locks scrollbars starting from an element
 * @param {HTMLElement} node - the element to start locking scroll at
 * @return {Function} unlockScroll - unlocks all scroll elements/parents
 */
function lockScroll(node, lockedNodes = []) {
  const viewport = getClosestViewport(node)
  if (viewport && !viewport.__locked) {
    const { overflow, paddingRight } = getComputedStyle(viewport)
    const previousStyles = {
      overflow: viewport.style.overflow,
      paddingRight: viewport.style.paddingRight,
    }
    lockedNodes.push([viewport, previousStyles])
    if (overflow !== 'hidden') {
      viewport.style.overflow = 'hidden'
      viewport.style.paddingRight =
        parseInt(paddingRight, 10) + getScrollbarWidth() + 'px'
    }
    if (viewport === document.body) {
      return () => {
        lockedNodes.forEach(([node, previousStyles]) => {
          node.style.overflow = previousStyles.overflow
          node.style.paddingRight = previousStyles.paddingRight
          delete node.__locked
        })
      }
    } else {
      return lockScroll(viewport.parentNode, lockedNodes)
    }
    viewport.__locked = true
  }
}