In most cases it is insecure to keep production and other environment settings within repository, but as you start a project it could the simplest way. Eventually we will have more advanced solution.
- index.js - this file contains common configuration for all environments (production, development, etc).
- development.js - all development configuration must be placed in here.
- test.js - all test configuration must be place in here.
Typically you would have one config file per environment. In runtime index config automatically merged with environment file, based on value of NODE_ENV environment variable, which we set to development if nothing else specified.
If for any reason you need to create your own local configuration for application or for tests - there are two special files local.js and test-local.js. They are in a .gitignore and can be used to change settings specifically in your local environment.