CODEWITHSUNDEEP
reactjsfirebase-realtime-databasereact-redux
chucknor
chucknor

Reputation: 849

Retrieving data from Firebase Realtime Database from React-redux app

I am trying to query data from my Firebase realtime database based on the child value matchID.

Below is the JSON export of my matchPredictions table with only one entry in it.

{
  "-LP0aVMsmqfdHj7yfPnK" : {
    "matchID" : "-LP0LKl_nR4VQf6Gxwz8",
    "matchKickoff" : "2019-01-12T12:00",
    "teamAName" : "Germany",
    "teamAScore" : "2",
    "teamBName" : "Denmark",
    "teamBScore" : "3",
    "userId" : "RZVbxcIB1SWxj0ohgJDqkEU9ia13"
  }
}

I have the following function which gets called ..

export const fetchPredictionsForCompletedMatch = (match, token) => {
    console.log("Match is " +match);
    console.log("matchPredictionsFBRef is " + matchPredictionsFBRef);
    const retrievePreds = matchPredictionsFBRef.orderByChild("matchID").equalTo(match).on("value",
        function(snapshot){
        console.log("Snapshot here is "+ snapshot);
    });
    return dispatch => {
        retrievePreds.then(
            response => dispatch(addMatchResultSuccess(match))
        )
            .catch(
                err => dispatch(addMatchResultFail(err))
            )
    }
}

The value for match is -LP0LKl_nR4VQf6Gxwz8 as expected and matchPredictionsFBRef is https://projectOne.firebaseio.com/matchPredictions, which is the table I am trying to query.

When this runs the error "The error is TypeError: retrievePreds.then is not a function" is thrown and snapshot is not printed to the console.

Any help would be much appreciated. Thanks.

Upvotes: 0

Views: 493

Answers (2)

Frank van Puffelen
Frank van Puffelen

Reputation: 598847

Firebase's on() method can give results multiple times. Since a promise can only resolve once, the on() method can't return a promise.

If you only want to get a result once, use Firebase's once() method instead of on():

const retrievePreds = matchPredictionsFBRef.orderByChild("matchID").equalTo(match).once("value",
  ...

Upvotes: 1

markymark
markymark

Reputation: 145

Can you call the function before chaining then.

retrievePreds().then()

Upvotes: 0

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