How to set host environment variables inside npm scripts(package.json)

Question

Imagine I have an environment variable

export NODE_ENV=production

when I do

echo $NODE_ENV //--> shows production which is correct

Problem:

Inside my package.json

scripts: {
...
"build": "export REACT_APP_NODE_ENV=${NODE_ENV:-development}; 
          npm run build-css && react-scripts build",
...
}

Now when I do npm run build REACT_APP_NODE_ENV is getting set to development...but it should have been production as NODE_ENV is present.

If I do

scripts: {
...
"build": "export REACT_APP_NODE_ENV=production; 
   npm run build-css && react-scripts build",
...
}

It works correctly as expected i.e. all scripts access the REACT_APP_NODE_ENV with expected value that is production.

Goal

I wish to avoid hardcoding in my package.json

How can I set REACT_APP_NODE_ENV with value ${NODE_ENV}

"build": "export REACT_APP_NODE_ENV=${NODE_ENV}; 
  npm run build-css && react-scripts build",

Answer 1

You probably want to ensure that this is cross-platform which will save you some headaches later on.

That problem has already been solved in the npm package cross-var.

Then, assuming you've already exported NODE_ENV, you use it this way:

"scripts": {
    "build": "REACT_APP_NODE_ENV=${NODE_ENV}"
}