$scope.cancelLabel = (!cancelLabel) ? cancelLabel : 'Cancel';which translates into:
<data-confirm:button class="btn btn-default" confirm-title="Confirm Clear" link-text="Clear E-Messages" confirm-message="'Are you sure you want to clear all e-messages?'" ok-label="Yes" cancel-label="No" disable-action ="currentOperator.EMessage" ok-action="clearEMessage(currentOperator)"></data-confirm:button>I want to disable the button if the eMessage is empty.