How to set NODE_ENV from package.json for react

As per the docs, we cannot override NODE_ENV, but there is a room to create our own custom variables starting with REACT_APP_. So i configured to look as below:

Reference: https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables

"staging": "concurrently -k  \"npm:staging-server\" \"cross-env REACT_APP_ENVIRONMENT='staging' PORT=3003 react-scripts start\"",

And inside my UI application, I can fetch its value by consoling it like this:
console.log('REACT_APP_ENVIRONMENT => ', process.env.REACT_APP_ENVIRONMENT);