https://github.com/Microsoft/Appsample-Photosharing/blob/master/PhotoSharingApp/PhotoSharingApp.AppService.Shared/Models/DocumentDB/js/getRecentPhotosForCategoriesStoredProcedure.js

getRecentPhotosForCategoriesStoredProcedure.js

// Store Procedure for getting the most recent photos for each category
//   @param numberOfPhotos - The number of photos to return per category
//   @param currentDocumentVersion - The current document version number that the service is using
function getRecentPhotosForCategories(numberOfPhotos, currentDocumentVersion) {
    let catCount = 0;
    let catIndex = 0;
    let existingPhotos = [];

    getAllCategories(function (allCategories) {
        for (var i = 0; i < allCategories.length; i++) {

            // Retrieve the most recent photos for this category
            // and append them to the response body
            getRecentPhotosForCategory(allCategories[i].id);
        }
    });

    function getAllCategories(callback) {
        // Perform Query using JavaScript Language Integrated Query.
        var result =__.filter(function(doc) {
            return doc.DocumentType == "CATEGORY" && doc.DocumentVersion == currentDocumentVersion;
        }, function(err, documents) {
            if (err) {
                throw new Error("Unable to query for all categories, aborting.");
            }
            if (documents.length < 1) {
                return;
            }
            catCount = documents.length;
            callback(documents);
        });
        if (!result.isAccepted) {
            throw new Error("Sproc is too close to violating resource limit, aborting.");
        }
    }

    function getRecentPhotosForCategory(categoryId) {

        // Perform Query using chained JavaScript Language Integrated Query.
        var result = __.chain()
        .filter(function(doc) {
                return doc.DocumentType == "PHOTO" && doc.CategoryId == categoryId && doc.DocumentVersion == currentDocumentVersion && doc.Status == 1;
            })
        .sortByDescending(function (photoDoc) { return photoDoc.CreatedDateTime.Epoch })
        .value({ pageSize: numberOfPhotos }, function (err, documents) {
            if (err) {
                throw new Error("Unable to query for photos in category " + categoryId + ", aborting.");
            }

            // Append the documents to our total collection
            existingPhotos = existingPhotos.concat(documents);
            ++catIndex;

            // Once we have iterated over every category, we can return
            // them all to the response.
            if (catIndex >= catCount) {
                __.response.setBody(existingPhotos);
            }
        });
        if (!result.isAccepted) {
            throw new Error("Sproc is too close to violating resource limit, aborting.");
        }
    }
}