1. DomName('KeyboardEvent.getModifierState')
  2. DocsEditable()
  3. Experimental()
bool getModifierState(String keyArgument)

Source 

@DomName('KeyboardEvent.getModifierState')
@DocsEditable()
@Experimental() // untriaged
bool getModifierState(String keyArgument) => _blink.BlinkKeyboardEvent.instance.getModifierState_Callback_1_(unwrap_jso(this), keyArgument);