utils/dom/containsnode

Checks whether node is inside container, looking through shadow roots on the way.

Use it instead of Node#contains(), which stops at a shadow root: that one says false even when container really is an ancestor, as long as a shadow root sits between the two. A node contains itself here, just like it does there.

container can also be a Document or a ShadowRoot – useful for a scroll event, for example, whose target is the document and not an element. Works with open and closed shadow roots.

Parameters

container: Node

The node that may be the ancestor.

node: Node | null

The node to look for. May be null, which always gives false.

Returns

boolean