javascript - Firebase .then with .on('value')

Question

I'm trying to get .then() to work with .on() but it only works with .once().

I get playersRef.on(...).then is not a function, when trying it with on()

So what I have now is this:

   let nodesRef = Firebase.database().ref('players')
   let answers = {}
   playersRef.on('value', (playersSnapshot) => {
      playersRef.once('value').then((playersSnapshot) => {
        playersSnapshot.forEach((playerSnapshot) => {
          let playerKey = playerSnapshot.key
          let answersRef = playerSnapshot.child('answers')
          if (answersRef .exists()){
            answers[playerKey ] = answersRef .val()
          }
        })
      }).then(() => {
        console.info(answers);
        dispatch(setPlayerAnswers(answers))
      })
    })

But I don't like the fact that it is querying the ref twice.

How would I go about getting each player's answer in this example? What would be a more correct way? Because I don't think this is the way the Firebase devs intended this.

And what is the reasoning that it is not implemented for .on()? Because playersSnapshot.forEach(...).then is also not a function... How do I execute something only once whenever the .on('value') triggers?

Answer 1

Waitting for answers