utils/dom/findclosestscrollableancestor

Returns the closest scrollable ancestor of a DOM element.

The search crosses shadow DOM boundaries, continuing from the host element of a shadow root instead of stopping at it. Without that, an element rendered inside a shadow tree would report no scrollable ancestor at all, even when one exists further up in the surrounding document, because the walk goes over parentElement, which is null for a direct child of a shadow root. Works for both open and closed shadow roots.

Parameters

domElement: HTMLElement

DOM element.

Returns

HTMLElement | null

First ancestor of domElement that is scrollable or null if such ancestor doesn't exist.