为什么“解析云代码”中的此Promise无效？

Question

The following Cloud Code function on Parse Server does not work as expected.

It seems to resolve too early so that not all chained promises of promise2 are executed. In particular I see some of the resultA.add(...); not being executed.

I have tried to re-arrange this several times without success.

I am not sure if return Parse.Promise.resolve(); is what I should return in the else clause or if it is something else or nothing.

Can anyone spot something here?

Parse.Cloud.define("aFunction", function(request, response) {

    var q = new Parse.Query("ClassA");    
    q.find()
    .then(
        function(resultsA) {

            var promise = new Parse.Promise.as();
            resultsA.forEach(function(resultA) {

                promise = promise
                .then(
                    function() {
                        var q = new Parse.Query("ClassB");
                        return q.first();
                    }
                )
                .then(
                    function(resultB) {

                        if (resultB != undefined) {
                            resultA.set(...);
                            return resultA.save();

                        } else {
                            resultA.set(...);
                            return resultA.save();
                        }
                    }
                )
                .then(
                    function() {

                        var q = new Parse.Query("ClassC");
                        return q.find()

                        .then(
                            function(resultsC) {
                                if (resultsC != undefined && resultsC.length > 0) {

                                    var promise2 = new Parse.Promise.as();
                                    resultsC.forEach(function(resultC) {
                                        promise2 = promise2
                                        .then(
                                            function() {
                                                resultA.add(...);
                                                return resultA.save();
                                            }
                                        );
                                    });
                                    return promise2;

                                } else {
                                    return Parse.Promise.resolve();
                                } 
                            }
                        );
                    }
                );
            });
            return promise;
        }
    )
    .then(
        function(result) {
            response.success("success");
        },
        function(error) {
            response.error(error.message);
        }
    );
});

Long code but I already stripped it down and wanted to show the actual structure. Thanks.

Answer 1

just checked your code. And i'm not sure if it's your type mistake , when you 'clean your code' for showing structure.

in your loop: chats.forEach(function(resultA) ..

It seems like you haven't declare 'chats' variable.

Also, as Parse official recommended , please try following:

var _ = require('underscore.js');

var promise = Parse.Promise.as();
_.each(resultsA, function(resultA) {

    promise = promise.then(function() {..}.then..then..
}
return promise;

Hope this can help you.