React Native How to fetch data from array in firebase

Question

This is my database structure below tutorCopy is the currentId of the user on basis of which I have to retrieve the user email but the problem is I can't get it, I have tried two methods but both are not working: 1st method with promise

componentWillMount(){

  let user = firebase.auth().currentUser.uid;
  const emailFetch = ["useremail"]
  const emailpromise = emailFetch.map(id => {
    return firebase.database().ref("tutorCopy/").child(user).child(id).on('value', s => s)
  })
  Promise.all(emailpromise)
    .then(user => {
      this.setState({ markers: s.values(s.val()) })

    })
    .catch(err => {
      console.log(err)
    })
}

Other one with snapshot:

componentWillMount(){
  var user = firebase.auth().currentUser.uid;
  var currId = JSON.stringify(user);
  firebase.database().ref("tutorCopy/").child('user').once("value", snapshot => {
    this.setState({ markers: Object.values(snapshot.val()) })
  })
}

This question already has an answer here: https://stackoverflow.com/questions/56659730/querying-array-from-firebase-react-native — Hedi KARRAY, Mar 30 '20 at 13:03
@rajan I have tried it, it says data is undefined in console — Talha Nadeem, Mar 30 '20 at 13:17
What is the meaning of the level under each user ID? I get that you have `/tutorCopy/$uid`. But can there be multiple `-M...` nodes under a UID? — Frank van Puffelen, Mar 30 '20 at 14:47
@FrankvanPuffelen the uid is basically current id coming from "tutor" table the reason why I took it is on the basis of that id the only specific tutur can view his data i.e if user with ID Xtrg.... logs in, he can view the email reffered to him. — Talha Nadeem, Mar 30 '20 at 15:30
So there can be multiple -M... nodes under a UID? If so, what doesn't work about the first code snippet you shared? — Frank van Puffelen, Mar 30 '20 at 15:57
@FrankvanPuffelen Yes! What I want to do is to get that useremail and save it in marker, but it return me null. — Talha Nadeem, Mar 30 '20 at 16:04
If there can be multiple `-M...` nodes under a UID, there can be multiple email addresses. How do you want to deal with that? — Frank van Puffelen, Mar 30 '20 at 23:34
Also note that the `s.values(s.val())` in your first snippet is not defined anywhere in that snippet. — Frank van Puffelen, Mar 30 '20 at 23:35
I just want to show these email address but I wont be able to fetch them — Talha Nadeem, Mar 31 '20 at 07:56

React Native How to fetch data from array in firebase

0 Answers0