Firebase cloud function sending multiple notification on instanceId - node.js

Question

Thats my code where i first get the laterrides. It checks that the any ride is schedule and if any ride is scheduled then it goes inside and get the list of drivers and sends them notification. But the issue is it send notification repeatedly again and again.Kindly help.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.testing = functions.https.onRequest((req, res) => {
console.log("start");
var newArray = [];
let date = new Date();
var hours = date.getHours() + 5;
var minute = date.getMinutes() ;
var year = date.getFullYear() ;
var month = date.getUTCMonth() + 1 ;
var day = date.getDate() ;
var total_date = day + "/" + month + "/" + year;
var total_time = hours + ":" + minute;
var ridelater = admin.database().ref("ridelater");
ridelater.orderByValue().on("value", function(snapshot) {
snapshot.forEach(function(data) {
var str = data.val().time;
const senderUid = data.val().client_key;
if(data.val().date == total_date){
var arr = str.split(":");
var start_minute = arr[0] * 60;
var val = parseInt(arr[1], 10);
var timing = val - 30;
var start = start_minute + timing ;
var end_minute = hours *60;
var end = end_minute + minute;
var diff = end - start;
if (diff <= 30){
var driver = admin.database().ref("user/driver");
driver.orderByValue().on("value", function(snapshot) {
snapshot.forEach(function(instnaceIds) {
//if(instnaceIds.val().status == "free"){
const promises = [];
const receiverUid = instnaceIds.key;
const getInstanceIdPromise =
admin.database().ref(`/user/driver/${receiverUid}/instanceId`)
.once('value');
const getSenderUidPromise = admin.auth().getUser(senderUid);
Promise.all([getInstanceIdPromise, getSenderUidPromise]).then(results =>
{
const instanceId = results[0].val();
//const sender = results[1];
console.log('notifying ' + receiverUid +' from ' + senderUid);
var data1={
'users_key': senderUid,
'org_address' : data.val().org_address,
'dest_address' : data.val().dest_address,
'status' : "request",
'Nodekey' : data.key,
'user_name' : data.val().user_name,
'org_lat' : data.val().org_lat,
'org_long' : data.val().org_long,
'dest_lat' : data.val().dest_lat,
'dest_long' : data.val().dest_long,
'payment' : data.val().payment_method,
'category' : data.val().category,
'Nodekey' : data.val().node_key,
};
var data2 = JSON.stringify(data1);
console.log(JSON.stringify(data1));
const payload = {
notification: {
title: "Qandeel Haider",
body: data2
}
};
console.log(payload);
return admin.messaging().sendToDevice(instanceId, payload)
.then(function (response) {
console.log("Successfully sent message:" + instanceId);
})
.catch(function (error) {
console.log("Error sending message:", error);
});
});
//}
});
});
}
else{
console.log("Not found" + data.val().time);
}
}
else{
console.log("Not found" + data.val().date);
}
console.log("IN");
});
});
console.log("end");
res.status(200).end();
});