I'm not sure if this is expected, but it doesn't feel right.

If I run an app with

$ REACT_APP_FOO=bar npm start

I can access process.env.REACT_APP_FOO, but REACT_APP_FOO in process.env returns false, and process.env["REACT_APP_FOO"] is undefined.

I'm trying to have something like:

function getConfig(key) { if (key in process.env) { return process.env[key]; } return defaults[key]; }