CODEWITHSUNDEEP
javascriptfirebasefirebase-realtime-database
user123456
user123456

Reputation: 181

Update and increment value with realtime database

Im trying to update the points of the child : add 40points to the old result points, but I get the error : undefined is not an object (Evaluating 'pointRef.update')

const pointRef=firebase.database().ref("Users").child(firebase.auth().currentUser.uid)
                            .once("value",(snapshot=>
                            {
                            pointRef.update({Points:snapshot.val().Points+40
                             })

Upvotes: 1

Views: 310

Answers (1)

Dharmaraj
Dharmaraj

Reputation: 50930

You are using .once() method on pointRef so it is no longer a DatabaseReference. It is a DataSnapshot now. So you cannot call the .update() method on it. Instead try using the following code:

const pointRef = firebase.database().ref("Users").child(firebase.auth().currentUser.uid)

pointRef.once("value").then((snapshot) => {
  pointRef.update({Points:snapshot.val().Points+40}).then(() => {
    console.log("Points updated")
  })
})

The better way of doing this:

firebase.database().ref("Users").child(firebase.auth().currentUser.uid)
    .set({Points: firebase.database.ServerValue.increment(40)})

Here you don't need to manually fetch, add and update the points field.

Upvotes: 2

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