I have a function calling promise from backend.It is a list of emails. What i am trying to is giving button a text according to the number of emails that user have. For example,If there is no email subtext will say you dont have a email add one etc..

return customerEmailService.getEmailList().then(function (emails) {
              if (emails.emailList.length === 0) {
                button.active = false;
                button.subtext = 'Mail Not Found';
                if (flowScope.get("emailWihoutDispense")) {
                  button.onClick = function () {
                    message.error(mailNotFoundErrorWithoutDispense());
                  };
                }...

button.OnClick is working fine but button.subtext is not seen in the screen and I want to wait this function to show the subtext on the screen.How can i do that?