What is the best way to share configs between backend and frontend?

I have backend built with Express.js and frontend built with Ember.js. In my git repo there are two folders with frontend and backend. I have file with constants on backend but I don't want to duplicate this file in frontend.

Also I could make request from frontend to backend to get these constants and further work with it from Ember.DS but I don't want redundant query to API.

I think best way to make module and add it into requirements on backend and on frontend. But for this I need to create separate repo and I think it's overhead.

Please recommend another good way to solve this problem.