Check if a ember object exists on the clients browser?

Say there exists some express and emberjs website ‘www.example.com’. The backend is a data centric api with a single route to serve static files (emberjs application). if a client visits ‘www.example.com/artist/album’, this route returns a JSON response. How can you check if emberjs is loaded in the clients browser?

Perhaps you can add a custom header see: Customizing Adapters - Models - Ember Guides so you know the json request is comming from the Ember App.