Call multiple registers in Realtime from Firebase Cloud 'at same time'

Question

I'm trying to send some pushes to users when a 'invitation' is written in Realtime DB.

When the cloud function detects the creation of the invitation is triggered, and recovers the users list to ve invited (id's).

Once I get this id's I have to recover the user info for each id, in order to get some info like language, fcmTokens, etc..

Reading some SO questions I saw that I have to create a reference to the "call" like:

admin.database().ref(`/user/${userId}`).once('value')

Then store it in an array and call with Promise.all()

var userPromises = [];
for (var i = 0;i<usersInRange.length; i++) {
     var userId = usersInRange[i];
     userPromises[i] = admin.database().ref(`/user/${userId}`).once('value');
}
Promise.all(userPromises).then(results => {
...
})

And here is where I need help.

I'm having some problems , because if Promise.all() fails in retrieving some user, it stops, and don't read the other id's.

There is a way to do it "one by one" to avoid Promise.all() stop?

Which action do you want to do on the documents you read? Modify them? Which kind of error you are expecting? — Renaud Tarnec, Nov 26 '19 at 12:59

score 0 · Answer 1 · answered Nov 25 '19 at 23:44

Here you can find a similar question which is already answered. Summarizing, they say that you can use an async function (if possible). Another approach is to use a loop.

function runSerial(tasks) {
    var result = Promise.resolve();
    tasks.forEach(task => {
      result = result.then(() => task());
    });
    return result;
}

It worth to take a look into it.

Call multiple registers in Realtime from Firebase Cloud 'at same time'

1 Answers1