vue-virtualized-table-booway/src/utils/dom/getScrollBarSize.js

The second version of implementation of `vue-virtual-table` component, it was inspired from [rc-table](https://github.com/react-component/table) and [ant-table](https://ant.design/components/table), API design is 60%+ consistent. Or you could think I tran

/* Forked from `https://github.com/react-component/util/edit/master/src/getScrollBarSize.js` */
let cached

export default function getScrollBarSize(fresh) {
  if (typeof document === "undefined") {
    return 0
  }

  if (fresh || cached === undefined) {
    const inner = document.createElement("div")
    inner.style.width = "100%"
    inner.style.height = "200px"

    const outer = document.createElement("div")
    const outerStyle = outer.style

    outerStyle.position = "absolute"
    outerStyle.top = 0
    outerStyle.left = 0
    outerStyle.pointerEvents = "none"
    outerStyle.visibility = "hidden"
    outerStyle.width = "200px"
    outerStyle.height = "150px"
    outerStyle.overflow = "hidden"

    outer.appendChild(inner)

    document.body.appendChild(outer)

    const widthContained = inner.offsetWidth
    outer.style.overflow = "scroll"
    let widthScroll = inner.offsetWidth

    if (widthContained === widthScroll) {
      widthScroll = outer.clientWidth
    }

    document.body.removeChild(outer)

    cached = widthContained - widthScroll
  }

  return cached
}