reactive var

maintenance.js

Template.maintenance.onCreated(function() {
    this.subscribed = new ReactiveVar(false);
    this.errorMessage = new ReactiveVar(null);
    this.subscribing = new ReactiveVar(false);
});

Template.maintenance.helpers({
    'subscribed': function () {
        return Template.instance().subscribed.get();
    },

    'errorMessage': function () {
        return Template.instance().errorMessage.get();
    },

    'subscribing': function () {
        return Template.instance().subscribing.get();
    }
});

Template.maintenance.events({
    'submit .mailchimp-form': function (e, template) {
        e.preventDefault();

        var $input = $(e.target).find('[type=email]');
        if (!$input.val()) {
            return;
        }

        Meteor.call('subscribeMailChimp', $input.val(), function (error, result) {
            if (error) {
                var message;
                switch (error.error) {
                    case 232:	// 'Email_NotExists'
                        message = 'Email not exists';
                        break;
                    case 214:	// 'List_AlreadySubscribed'
                        message = 'Already subscribed!';
                        break;
                    default:
                        message = 'Subscribe error';
                }
                template.errorMessage.set(message);
            } else {
                template.subscribed.set(true);
                $input.val('');
            }
        });
    }
});