Keeping secrets in a node app

For some time I was looking for a way to safely store my app secrets like API keys. Environment variables are OK, they work, but I found it cumbersome. I had a Heroku project where this worked with a .env file that looked like this:

FIREBASE_BNM_SECRET=THE_VALUE

Nice, useful, and simple. It gave me a way to neatly store production and development secrets. I was wondering how would I get a as simple thing for my other node apps, and today I came up wit secrets.json:

{
  "FIREBASE_BNM_SECRET": "THE_VALUE"
}

Now I simply say var secrets = require('./secrets'); and I have them handy. Nice, useful and simple.