Yet Another Google Firebase Error "Function returned undefined, expected Promise or value"

Question

I've read all the related questions and watched the Firebase videos re Promises and I still can't get rid of the above error. The attached code runs fine locally, yet when done from cloud functions I keep on getting this error. Any help would appreciated!

exports.enquiry = functions.firestore.document('users/{userId}/enquiries/{enquiryId}')
    .onCreate((snap, context) => {
        let enquiryDoc = snap.data();
        let {
            uid,
            type
        } = enquiryDoc;



        function ResponseGeneration(type) {
            switch (type) {
                case 'type1':
                    {
                        Response = 5;
                        return Promise.resolve(Response);
                    }

                case 'type2':
                    {
                        var body = `<QUOTA><DATE>20181203</DATE></QUOTA>`;

                        const call = request.post({
                                url: "xxx",
                                port: 443,
                                method: "POST",
                                headers: {
                                    'Content-Type': 'text/xml',
                                },
                                body: body,
                                json: false
                            })
                            .then((parsedBody) => {
                                console.log(parsedBody.statusCode);
                                console.log(parsedBody);
                                return xml2js(parsedBody);
                            })
                            .then((js) => {
                                console.log('JSON.stringify(js):', JSON.stringify(js));
                                var json = JSON.stringify(js);
                                var jsonParsed = JSON.parse(json);
                                if (jsonParsed.hasOwnProperty('Error')) {
                                    Response = jsonParsed['Error']['Message'];
                                } else {
                                    Response = jsonParsed['RESULT'];
                                }
                                console.log("Response: ", Response);

                                return Promise.resolve(Response);

                            }).catch(function(err) {
                                console.log("error from post:", err);
                                // return Promise.resolve(err);
                            });

                        return Promise.all(call); //also tried with Promise.resolve
                    }

                default:
                    return Promise.resolve(0.0);
            }
        }

        ResponseGeneration(type).then((response) => {
            return snap.ref.update({
                quote: response,
                status: 'quoted',
                quoteId: context.params.enquiryId
            });
        });
    });

As you can see, it returns Promises everywhere, yet Firestore console keeps printing:

Function returned undefined, expected Promise or value

I'm not quite seeing where else it might be missing a promise. Any help?

Answer 1

Your top level function called by onCreate() isn't returning anything, thus the error.

You need to return the Promise from your call to ResponseGeneration:

    return ResponseGeneration(type).then((response) => {
        return snap.ref.update({
            quote: response,
            status: 'quoted',
            quoteId: context.params.enquiryId
        });
    });