1. @DomName('WorkerGlobalScope.btoa')
  2. @DocsEditable()
  3. @Experimental()
String btoa(String btoa)

Source 

@DomName('WorkerGlobalScope.btoa')
@DocsEditable()
@Experimental() // untriaged
String btoa(String btoa) =>
    _blink.BlinkWorkerGlobalScope.instance.btoa_Callback_1_(this, btoa);