Grapherjs How to set limit and sort on server only

#1

I use grapher for subscribe

Client

import Conversation from './collection';
import Customer from '../customer/collection';

Conversation.addLinks({
    'customer': {
    	type: 'one',
        field: 'customer_id',
        collection: Customer
    }
});

export default Conversation.createQuery('converation_items', 
{
    $options: 
    {
        limit:50,
        sort: 
        {
            'last_updated': -1,
        },
    },
    created_at: 1,
    source_name:1,
    unread_message:1,
    last_message:1,
    last_updated:1,
    is_pinned:1,
    customer:{
        full_name:1,
        avatar:1
    }
});

Server

import { Meteor } from 'meteor/meteor';
import itemsQuery from './items';
import Validate from '../../_helpers/validate';
import _ from 'lodash';

itemsQuery.expose({
    firewall(filters, options) 
    {
        filters.completed   = false;
    },
/*
    maxLimit: 10, 
    publication: true,
    method: false,
    blocking: false,
    maxDepth: 2,
    */
});

how to set $options on server only not allow set on client

$options: 
    {
        limit:3,
        sort: 
        {
            'last_updated': -1,
        },
    },

Thank you.