/* eslint-disable no-cond-assign, no-continue */ import css from './css'; import height from './height'; import isDocument from './isDocument'; /** * Find the first scrollable parent of an element. * * @param element Starting element * @param firstPossible Stop at the first scrollable parent, even if it's not currently scrollable */ export default function scrollParent(element, firstPossible) { var position = css(element, 'position'); var excludeStatic = position === 'absolute'; var ownerDoc = element.ownerDocument; if (position === 'fixed') return ownerDoc || document; // @ts-ignore while ((element = element.parentNode) && !isDocument(element)) { var isStatic = excludeStatic && css(element, 'position') === 'static'; var style = (css(element, 'overflow') || '') + (css(element, 'overflow-y') || '') + css(element, 'overflow-x'); if (isStatic) continue; if (/(auto|scroll)/.test(style) && (firstPossible || height(element) < element.scrollHeight)) { return element; } } return ownerDoc || document; }