I'm having great difficulty performing an action with firebase Realtime data.

I have this structure:

-contacts
  --id
    ---name
    ---status
    ---valor

For example:

I'm trying to SUM all records with "RECEITA" status,with this code:

const filterStatus = () => {
    fireDb.child("contacts").orderByChild("status").equalTo("Receita").on("value", (snapshot)  => {
        if(snapshot.val()) {
          var sum = 0;
          Object.keys(data).map((id, index) => {        
          sum += parseInt(data[id].valor);  
          console.log(sum)         
          })  
        }
    } 
  ) 
}

but it's not returning anything, not even in console.log

How can I do this sum correctly?