how to return promise in firebase set()

Question

I want to receive success if data is pushed correctly to firebase or catch an error if rejected. I tried such a code:

db.push().set(todo).then(snap => {
      console.log(snap);

    });

but SNAP, callback, IS UNDEFINED . How do I need to use promises here?

Answer 1

The .then does not return a snapshot of the data -- you will need to do a "once" snapshot of the data within the callback

db.push().set(values).then(() => {
  console.log('Successfully set');

  db.once('value').then((snap) => {
    console.log(snap);
  });
});