1. @DomName('DOMTokenList.supports')
  2. @DocsEditable()
  3. @Experimental()
bool supports(String token)

Source 

@DomName('DOMTokenList.supports')
@DocsEditable()
@Experimental() // untriaged
bool supports(String token) =>
    _blink.BlinkDOMTokenList.instance.supports_Callback_1_(this, token);