Backbone.js Loading notification

app.coffee

activeRequests = []

Backbone._sync = Backbone.sync
Backbone.sync = (method, model, options) ->
  asyncToken = Backbone._sync.apply(this,arguments)
  asyncToken.then () ->
    activeRequests = _.without activeRequests, asyncToken
    if activeRequests.length == 0 then console.log "LOADING COMPLETE"
  if activeRequests.length == 0
    console.log "START LOADING"
  activeRequests.push asyncToken