Issues With Parse Cloud Code Promises

I am trying to work with Parse Cloud Code and use promises to make sure I eliminate any issues with cals being async. I am wanting to query a class, get an object back, build up so

Solution 1:

There are several issues :

• Confusion between projectsData and projectData
• projectsData isn't actually necessary.
• projectData needs to be in scope in the three places it is (or should be) used after it is created & assigned.
• In several cases .then() is used where standard synchronous flow will suffice. Purging the unnecessary .thens will help greatly in sorting out the scope issues.

Doing little more than shuffling the code around, I arrive at the following :

Parse.Cloud.define('getProject', function(request, response) {
    var Projects = Parse.Object.extend("projects"); // with credit to @kRiZvar query = new Parse.Query(Projects);
    query.equalTo('projectUrl', request.params.projectUrl);
    query.find().then(function(projectsResult) {
        var project = projectsResult[0];
        var projectData = {
            'id': project.get('id'),
            'title': project.get('title'),
            'previewImage': project.get('previewImage'),
            'longDescription': project.get('longDescription'),
            'shortDescription': project.get('shortDescription'),
            'visibleToPublic': project.get('visibleToPublic'),
            'dateStart': project.get('dateStart'),
            'dateEnd': project.get('dateEnd'),
            'updatedAt': project.get('updatedAt'),
            'projectStatus': project.get('projectStatus')
        };

        //Now make the tags query and the referees query in parallel.var tagsPromise = project.relation('tags').query().find();
        var refereesPromise = project.relation('referees').query().find();

        // Aggregate the two promises with Parse.Promise.when(), and handle the responses.return Parse.Promise.when(tagsPromise, refereesPromise).then(function(tags, referees) {
            //Process the tags response
            projectData.tags = tags.map(function(t) {
                return {
                    'tag': t.get('tag')
                };
            });
            //Process the referees response
            projectData.referees = referees.map(function(r) {
                return {
                    'name': r.get('name'),
                    'role': r.get('role'),
                    'emailAddress': r.get('emailAddress'),
                    'phoneNumber': r.get('phoneNumber'),
                    'linkedInUrl': r.get('linkedInUrl')
                };
            });
            // Yay!
            response.success(projectData);
        });
    }).fail(function(error) {
        response.error('Error: ' + error);
    });
});

Apart from the overall rearrangement, the only substantial changes are :

• Using Array#map() to map an array to another array.
• Making two queries in parallel and using Parse.Promise.when() to aggregate the two promises.

Solution 2:

The problem appears to be with your initial query. You are trying to use subclasses, but your syntax is wrong.

Your query should begin like this:

var Projects = Parse.Object.extend("projects");
var query = new Parse.Query(Projects);

EDIT:

Also, you are returning objects, you should return promises. See code below (not tested):

Parse.Cloud.define('getProject', function(request, response) {
    var projectUrl = request.params.projectUrl;
    var projectsData = [];

    varProjects = Parse.Object.extend("projects");
    var query = newParse.Query(Projects);
    query.equalTo("projectUrl", projectUrl);
    query.find().then(function(projectsResult) {
        console.log(projectsResult.length + " Projects returned");

        var project = projectsResult[0];
        var projectData = {
            "id": project.get("id"),
            "title": project.get("title"),
            "previewImage": project.get("previewImage"),
            "longDescription": project.get("longDescription"),
            "shortDescription": project.get("shortDescription"),
            "visibleToPublic": project.get("visibleToPublic"),
            "dateStart": project.get("dateStart"),
            "dateEnd": project.get("dateEnd"),
            updatedAt: project.get("updatedAt"),
            projectStatus: project.get("projectStatus")
        };

        projectsData.push(projectData);
        console.log("Step 1. Projects Data: " + JSON.stringify(projectsData));

        // Removed the return from herevar tagsData = [];
        console.log("Project Step 2: " + JSON.stringify(project));
        var tagsQuery = project.relation('tags');
        return tagsQuery.query().find();
    }).then(function(tags) {
        for(var t = 0; t < tags.length; t++) {
            var tagData = {
                "tag": tags[t].get("tag"),
            }
            tagsData.push(tagData);
        }
        projectsData.tags = tagsData;
        console.log("Step 2. Tags Data: " + JSON.stringify(tagsData));

        // Removed return from herevar refereesData = [];
        var refereesQuery = project.relation('referees');
        return refereesQuery.find();
    }).then(function(referees) {
        for(var r = 0; r < referees.length; r++) {
            var refereeData = {
                "name": referees[r].get("name"),
                "role": referees[r].get("role"),
                "emailAddress": referees[r].get("emailAddress"),
                "phoneNumber": referees[r].get("phoneNumber"),
                "linkedInUrl": referees[r].get("linkedInUrl"),
            }
            refereesData.push(refereeData);
        }
        projectData.referees =refereesData;
        console.log("Step 3. Referees Data: " + JSON.stringify(refereesData));

        response.success(projectsData);
    }, function(error) {
        response.error("Error: " + error);
    });
});

See Parse documentation here on retrieving data using subclasses.