I have a package.json with following (simplified) content in the scripts key:
... scripts: { \"start\": \"NODE_ENV=${NODE_ENV:=production} node start-app.js\"
If you have small use cased, use better-npm-run. For small cases, it works fine. Somehow if you have a lot of commands and it hard manage. Try, batman-cli. Work well and handle lot of environment-dependent issues
npm i -g batman-cli