firebase-event-stream

import Firebase from 'firebase'
import eventStream from 'firebase-event-stream'

const ref = new Firebase('https://some.firebaseio.com/')
const events = ['child_added']

const stream = eventStream(ref, { events })
  .on('data', ({ event, child }) => console.log('emitted ', event, child.val()))

ref.push({ foo: 1 })
ref.push({ foo: 2 })

// log emitted  child_added { foo: 1 }
// log emitted  child_added { foo: 2 }