function returned undefined and promises is not defined in functions firebase

Question

This is my first firebase function and it gives me a lot of headic :) The purpose is to update the count field from all documents from collection users every 24 hours.

    async function clearCountField() {
  console.log("Clearing count task start point.");
    const userSnapshots = db.collection('users').where('count', '!=', '').where('nou', '==', false).get().then(snapshot => {
      const promises = [];
      snapshot.forEach(doc => {
        promises.push(doc.ref.update({ 'count': '' }));
      });
    });
    return Promise.all(promises)
}



export const ClearCountField24h = functions.pubsub.schedule('0 0 * * *')
  .timeZone('Europe/Bucharest') //  timezone 
  .onRun((context) => {
   const promise = clearCountField().then(resolve,reject); 
});

what do I do wrong?

Answer 1

The promises created in the forEach loop are never resolved because Promise.all() is being returned before the query completes. Fix it like this:

async function clearCountField() {
  const query = db.collection('users').where('count', '!=', '').where('nou', '==', false);
  return query.get().then(snapshot => {
    const promises = snapshot.docs.map(doc => doc.ref.update({ 'count': '' }));
    return Promise.all(promises)
  }
}

The then in your export function is superfluous. Just return the promise from clearCountField()

export const ClearCountField24h = functions.pubsub.schedule('0 0 * * *')
  .timeZone('Europe/Bucharest') //  timezone 
  .onRun((context) => {
    return clearCountField();
});

Answer 2

Changing the following:

export const ClearCountField24h = functions.pubsub.schedule('0 0 * * *')
  .timeZone('Europe/Bucharest') //  timezone 
  .onRun((context) => {
    const promise = clearCountField().then(resolve,reject); 
  }
);

To this:

export const ClearCountField24h = functions.pubsub.schedule('0 0 * * *')
  .timeZone('Europe/Bucharest') //  timezone 
  .onRun((context) => {
    return clearCountField().then(resolve,reject); 
  }
);

Made one issue go away... but when testing the function the Error: ReferenceError: promises is not defined still remains...