Is the purpose of having this fresh data from the finishings.json file to enable every application user to be aware of new data in that file?
I mean... if me as user A am adding a new finishing, you want my finishing to be accounted by every other application user? Is that part of the suggestion algorithm?
If this is the case, and in fact what you're looking for is some sort of changes listener, you would have two options to solve this:
a) Using $timeout to pool the file every x seconds (I personally don't like this kind of approach).
b) Create a service that uses some form of WebSockets implementation (Socket.io, SignalR, etc). At an high level it would work this way: Your clients connect to the socket server/hub and subscribe to a data change event. Then, everytime a finishing is added to the file, you would then emit a data change event to the socket server which in turn would broadcast that event to every connected client.