Vulcan/packages/telescope-singleday/lib/client/templates/single_day_nav.js

Template.singleDayNav.created = function(){

  $(document).unbind('keyup'); //remove any potential existing bindings to avoid duplicates

  var currentDate = moment(Session.get('currentDate')).startOf('day');
  var today = moment(new Date()).startOf('day');

  $(document).bind('keyup', 'left', function(){
    Router.go($('.prev-link').attr('href'));
  });

  $(document).bind('keyup', 'right', function(){
    if(Users.is.admin(Meteor.user()) || today.diff(currentDate, 'days') > 0)
      Router.go($('.next-link').attr('href'));
  });

};

Template.singleDayNav.helpers({
  currentDate: function(){
    var currentDate = moment(Session.get('currentDate'));
    var today = moment(new Date());
    var diff = today.diff(currentDate, 'days');
    if (diff === 0) {
      return i18n.t("today");
    }
    if (diff === 1) {
      return i18n.t("yesterday");
    }
    return currentDate.format("dddd, MMMM Do YYYY");
  },
  previousDateURL: function(){
    var currentDate = moment(Session.get('currentDate'));
    var newDate = currentDate.subtract(1, 'days');
    return getDateURL(newDate);
  },
  showPreviousDate: function(){
    // TODO
    return true;
  },
  nextDateURL: function(){
    var currentDate = moment(Session.get('currentDate'));
    var newDate = currentDate.add(1, 'days');
    return getDateURL(newDate);
  },
  showNextDate: function(){
    var currentDate = moment(Session.get('currentDate')).startOf('day');
    var today = moment(new Date()).startOf('day');
    return Users.is.admin(Meteor.user()) || (today.diff(currentDate, 'days') > 0);
  }
})