Saving data to child in Firebase - firebase

Question

I have a small application where users can upvote or downvote players based on their recent performance in various sports.
When the upvote button is currently clicked, the UID of the voter (logged in via Google) is supposed to get pushed into the database of the corresponding player who was voted on. Like this:
However, instead, it's currently doing this:
Here is the code which is doing the Firebase work. I believe it is one of these lines that I have wrong.
this.database.child(playerId).transaction
or
ref = firebase.database().ref('players/voters');
The code:
this.database = firebase.database().ref().child('players');
upvotePlayer(playerId) {
this.state.user ?
this.database.child(playerId).transaction(function (player) {
if (player) {
console.log("UID: " + uid)
var ref = firebase.database().ref('players/voters');
ref.child(uid).set(1);
}
return player;
})
:
console.log("Must be logged in to vote.")
}

Answer 1

you're storing the votes in this path players/voters while it should be in this path players/$playerId/voters
checkout this
this.database = firebase.database().ref().child('players');
upvotePlayer(playerId) {
this.state.user ?
this.database.child(playerId).transaction(function (player) {
if (player) {
console.log("UID: " + uid)
var ref = firebase.database().ref('players/' + playerId + '/voters');
ref.child(uid).set(1);
}
return player;
})
:
console.log("Must be logged in to vote.")
}
transaction method have transactionUpdate function as argument which should return the new value and you didn't return any , also I think better solution is not use transaction
Edit : solution without transaction
upvotePlayer(playerId)
{
if(this.state.user)
{
let ref = firebase.database().ref('players/' + playerId + '/voters');
ref.child(uid).set(1);
}
else
{
console.log("Must be logged in to vote.")
}
}

Answer 2

The problem is because of this:
var ref = firebase.database().ref('players/voters');
it is adding the voters under the players node and not under the push id node.
So you have to retrieve the pushid from the database and then do this:
var ref=firebase.database().ref().child('players').child(playerId).child('voters');
so the voters will become one of the pushid child.
For Future Viewers:
It is better to use transactions since:
Using a transaction prevents upvote counts from being incorrect if multiple users upvote the same post at the same time or the client had stale data

Answer 3

Actually you are pushing the value to payers node with player id. you have push the data to child node of players id voters. Try this code:-
this.database = firebase.database().ref().child('players');
upvotePlayer(playerId) {
this.state.user ?
this.database.child(playerId).transaction(function (player) {
if (player) {
console.log("UID: " + uid)
player.ref.child(voters).push(uid);
}
return player;
})
console.log("Must be logged in to vote.")
}
Problem is your are actually taking the reference of players node and creating new node at same level of playerid named voters. Below line just create a new node voters at same level to playerid.
var ref = firebase.database().ref('players/voters');
ref.child(uid).set(1);
as you can see there is no node named voters in players root node. But you are setting the value so it is been created with new data using set() function