inferno-window/src/domHelpers.js

Inferno components for efficiently rendering large, scrollable lists and tabular data. NOTE: this is a port from the origin project written in react by @bvaughn

// @flow

let size: number = -1;

// This utility copied from "dom-helpers" package.
export function getScrollbarSize(recalculate?: boolean = false): number {
  if (size === -1 || recalculate) {
    const div = document.createElement('div');
    const style = div.style;
    style.width = '50px';
    style.height = '50px';
    style.overflow = 'scroll';

    ((document.body: any): HTMLBodyElement).appendChild(div);

    size = div.offsetWidth - div.clientWidth;

    ((document.body: any): HTMLBodyElement).removeChild(div);
  }

  return size;
}