1. DomName('Selection.containsNode')
  2. DocsEditable()
  3. Experimental()
bool containsNode(Node node, bool allowPartialContainment)

Source 

@DomName('Selection.containsNode')
@DocsEditable()
@Experimental() // non-standard
bool containsNode(Node node, bool allowPartialContainment) => _blink.BlinkSelection.instance.containsNode_Callback_2_(this, node, allowPartialContainment);