Env for laravel/elixir with browserify

Question

what is the solution for using environment variables in javascript projects with browserify?
In my current project I'm using laravel with elixir and browserify and I was trying to add envify but I don't know how to implement it into my elixir code:

//gulpfile.js

elixir(function(mix) {
   mix.browserify(['app.jsx'], 'public/js/app.js');
});

Basically I need env for api urls (dev/prod) so it would be best to have .env.json in the root and then somehow get those variables into my js code.

Any ideas or better solutions?