how-to-firebase-3-cursor-pagination.js

var axios = require('axios');
var firebase = require('firebase').initializeApp({
  "serviceAccount": "./service-account.json",
  "databaseURL": "https://quiver-two.firebaseio.com/"
});

var ref = firebase.app().database().ref();
var peopleRef = ref.child('swapi/people');
// Calling ref.toString() outputs the ref's entire path: https://...firebaseio.com/some/ref/path
var peopleUrl = peopleRef.toString() + '.json?shallow=true'; 
var pageLength = 2;

function getPages(accumulator, cursor) {
  var pages = accumulator || [];
  var query = peopleRef.orderByKey().limitToFirst(pageLength + 1); // limitToFirst starts from the top of the sorted list
  if (cursor) { // If no cursor, start at beginning of collection... otherwise, start at the cursor
    query = query.startAt(cursor);  // Don't forget to overwrite the query variable!
  }

  return query.once('value')
    .then(function (snaps) {
      var page = [];
      var extraRecord;
      snaps.forEach(function (childSnap) {
        page.push({
          id: childSnap.ref.getKey(),
          name: childSnap.val().name
        });
      });
      
      if (page.length > pageLength) {
        extraRecord = page.pop();
        pages.push(page);
        console.log(pages, extraRecord.id);
        return getPages(pages, extraRecord.id);
      } else {
        pages.push(page);
        return Promise.resolve(pages);
      }
    });
};
getPages()
  .then(function (pages) {
    console.log('pages', JSON.stringify(pages));
  });