Firebase nodejs admin fanout with Salada objects and GeoFire

fanoutFunction.js

var functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp(functions.config().firebase);

const db = admin.database().ref();
// Salada uses versions to help you structure your 
// new design in other version object
const version = 'v1/';

exports.fanoutPost = functions.database.ref(version + "post/{postId}")
.onWrite(event => {
  const postId = event.params.postId;
  console.log('event', event); 
  let data = event.data.previous.val(); // the post before changes
  let newData = event.data.val(); // updated post
  // you can make these if else statements one line, if you want to
  // I have done this way, maybe because you need to do extra work
  // based on actions 
  // when a post is deleted
  if(!event.data.exists()) {
    console.log('deleted part');
    fanout(postId, data, newData)
  }
  // when a post is updated
  else if (event.data.previous.exists()) {
    console.log('updated part');
    fanout(postId, data, newData)
  }
 // when new post is created
 else{
   console.log('added part');
   fanout(postId, newData, newData)
 }
});
function fanout(postId, data, newData){
  var dataToPost = dataToFanout(postId, data, newData)
  db.update(dataToPost, function(error){
    console.log('delete error',error);
  });
}
function dataToFanout(postId, data, newData) {
  var fannedOutData = {};
  fannedOutData[version + 'userPost/' + data.userId + '/' + postId] = newData;
  fannedOutData[version + 'cityPost/' + data.country + '/' + data.city + ' ' + data.state + '/' + data.sportType + '/' + postId] = newData;
  
  // if the event is deletion then delete the geofire objects
  if(newData == null){
    fannedOutData[version + 'postLocation/' + postId] = newData;
  }
  console.log('fanout data ', fannedOutData);
  return fannedOutData;
}

Fanout is pretty important on Firebase if you want to query more than one field. Here you can find fanout example. This covers updating, deleting and creating. I have used salada objects for data crud operations you can find it here. I hope this could help you since there is no example on fanout on firebase nodejs functions (server side).