CODEWITHSUNDEEP
javascriptangularfirebasegoogle-cloud-firestoregoogle-cloud-functions
BOOnZ
BOOnZ

Reputation: 848

cloud functions onCall - how to return an object

I am trying to read the return value of a google cloud functions onCall function but I keep reading null.

This is my angular code:

const callable = this.angularFireFunctions.httpsCallable('createEvent');
callable(this.formGroup.value).toPromise()
.then((next) => {
  console.log(next); //function succeeds but returned null
})
.catch((err) => {
  console.log(err);
})

I have the following cloud function defined. Everything is bundled inside a transaction.

export const createEvent = functions.https.onCall((data: any, context: CallableContext) : any | Promise<any> =>
{
    const user_DocumentReference = db.collection('users').doc(context.auth?.uid);
    const event_DocumentReference = db.collection('events').doc();

    db.runTransaction((transaction: FirebaseFirestore.Transaction) =>
    {
        return transaction.getAll(user_DocumentReference)
        .then((documentSnapshots: FirebaseFirestore.DocumentSnapshot<any>[]) =>
        {
            const user_DocumentSnapshot = documentSnapshots[0].data();

            if (typeof user_DocumentSnapshot === 'undefined')
            {
                // return some error message json object
            }

            transaction.create(event_DocumentReference,
            {
                //json object
            });

            //return success object with few attributes
        })
        .catch((firebaseError: FirebaseError) =>
        {
            //return some error message json object
        }
    });
});

How can I return json objects as a promise? I have tried the following to no avail:

return Promise.resolve({ json object });
return Promise.reject({ json object });

Upvotes: 0

Views: 1004

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317487

Your top-level function should return a promise that resolves with the data to send to the client. Returning that value from your transaction handler isn't enough. You'll need a return at the top level as well. Start with this:

return db.runTransaction(transaction => { ... })

As you can see from the API docs, runTransaction returns the promise returned by the transaction handler (or "updateFunction").

Upvotes: 2

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