complex use case for API calls utilizing jQuery deferreds

jquery deferred api calls.js

// outer IIFE - gives us $ === jQuery!, also, makes every var/function inside "private"!
window.MYAPI = (function($) {


function processSiteRequest( data ) {
    var sites = data.response.sites;
    
    // loop through each site given back for the paginated result set
    $.each( sites || [], function(index, site) {
        debugPrint("Site: " + site.name);
        $.each( site.content_categories || [], function( index, category ) {
            // build up category to publisher map
            debugPrint("    Category: " + category.name);
            if ( category.id in category_publisher_map ) {
                debugPrint("! category in map");
                category_publisher_map[category.id].publishers[site.publisher_id] = {publisher_name: site.publisher_name};
            }
            else {
                debugPrint("! category new so inserting as key in map");
                publisher_entry = {};
                publisher_name = site.publisher_name;
                publisher_entry[site.publisher_id] = {publisher_name: publisher_name};
                category_publisher_map[category.id] = {
                    name: category.name,
                    publishers: publisher_entry
                };
            }
        });

    });
}



function collectSites( ) {
    
    var site_def = $.Deferred();
    var start_element_list,
        requests_to_make,
        requests_made;


    function SitePaginationRequests( number_of_items ) {

        function buildSiteRequests( start_element ) {

            var def = $.Deferred();

            var query_data = {
                start_element: start_element,
                num_elements: NUM_ELEMENTS
            };

            $.getJSON('http://sand.api.whatever.com/site', query_data)
                .pipe(processSiteRequest)
                .done(function( data ) {
                    site_def.notify( ++requests_made / requests_to_make );
                    def.resolve( data );
                });
            return def.promise();
        }
        console.log( start_element_list, start_element_list.length );
        if ( start_element_list.length ) {
            var chunkedRequests = $.map(start_element_list.splice(0,2), buildSiteRequests);
            // recursion, is this the right approach?
            $.when.apply(null, chunkedRequests).done(SitePaginationRequests);
        }
        else {
            site_def.resolve();
        }
    }

    return $.getJSON('http://sand.api.whatever.com/site').pipe(function(data) {
        var number_of_items = data.response.count;
        start_element_list = _.range(0, number_of_items, NUM_ELEMENTS);
        requests_to_make = start_element_list.length;
        requests_made = 0;
        SitePaginationRequests( number_of_items );
        return site_def.promise();
    });

}


function getPublishersWithSelectedCategory( ) {

    return $.when( collectSites(), collectPlacements() ).progress(function(sites, placements) {

        max_site_progress = findMaxProgressPercent( sites );
        max_placement_progress = findMaxProgressPercent( placements );
        progress_percent =  Math.floor(( max_site_progress + max_placement_progress ) * 100 / 2) + "%";
        $("#gathering-progress-bar .bar").width( progress_percent );

    }).pipe(function() {
        console.log("Done with Service Calls");
        return category_publisher_map;
    });
}

// close the IIFE, and return our "public interface"
return {
    getPublishersWithSelectedCategory: getPublishersWithSelectedCategory
};
})(jQuery);