Firebase: Join an index of companies a user belongs to the data for the companies and display the results

fetch_manually.js

var fb = new Firebase('https://<INSTANCE>.firebaseio.com');

var idxRef = fb.child('users/kato/companies');
var dataRef = fb.child('companies');

idxRef.on('child_added', function(userSnap) {
  dataRef.child(userSnap.key()).once('value', function(snap) {
    console.log('user ' + userSnap.key() + ' belongs to company ' + snap.key());
  });
});

use_util.js

var fb = new Firebase('https://<INSTANCE>.firebaseio.com');

var dataRef = Firebase.util.NormalizedCollection(
    [fb.child('users/kato/companies'), 'idx'],
    [fb.child('companies'), 'company']
  )
  .select(
    {key: 'idx.$key', alias: 'uid'},
    'company.name'  
  )
  .ref();
  
dataRef.on('child_added', function(snap) {
  var data = snap.val();
  console.log('user ' + data.uid + ' belongs to company ' + data.name);
})