@popperjs/core/lib/dom-utils/getDecorations.js

Tooltip and Popover Positioning Engine

import getBorders from "./getBorders.js";
import getNodeName from "./getNodeName.js";
import getWindow from "./getWindow.js";
import getWindowScrollBarX from "./getWindowScrollBarX.js"; // Borders + scrollbars

export default function getDecorations(element) {
  var win = getWindow(element);
  var borders = getBorders(element);
  var isHTML = getNodeName(element) === 'html';
  var winScrollBarX = getWindowScrollBarX(element);
  var x = element.clientWidth + borders.right;
  var y = element.clientHeight + borders.bottom; // HACK:
  // document.documentElement.clientHeight on iOS reports the height of the
  // viewport including the bottom bar, even if the bottom bar isn't visible.
  // If the difference between window innerHeight and html clientHeight is more
  // than 50, we assume it's a mobile bottom bar and ignore scrollbars.
  // * A 50px thick scrollbar is likely non-existent (macOS is 15px and Windows
  //   is about 17px)
  // * The mobile bar is 114px tall

  if (isHTML && win.innerHeight - element.clientHeight > 50) {
    y = win.innerHeight - borders.bottom;
  }

  return {
    top: isHTML ? 0 : element.clientTop,
    right: // RTL scrollbar (scrolling containers only)
    element.clientLeft > borders.left ? borders.right : // LTR scrollbar
    isHTML ? win.innerWidth - x - winScrollBarX : element.offsetWidth - x,
    bottom: isHTML ? win.innerHeight - y : element.offsetHeight - y,
    left: isHTML ? winScrollBarX : element.clientLeft
  };
}