knockoutExtensions.js

            /*
             * read-only date display with momentjs
             * use like this: data-bind="moment: dateVar, format: 'YYYY-MM-DD'"
             * The "format" is optional and will default to "MM/DD/YYYY"
             */
            ko.bindingHandlers.moment = {
                update: function (element, valueAccessor, allBindingsAccessor, viewModel) {
                    var val = valueAccessor();
                    var date = moment(ko.utils.unwrapObservable(val));

                    var format = allBindingsAccessor().format || 'MM/DD/YYYY';

                    element.innerText = date.format(format);
                }
            };

thanks, solved my problem with knockout js and systemjs modules. I just changed the default format to 'L'