I have a package.json with following (simplified) content in the scripts key:
...
scripts: {
\"start\": \"NODE_ENV=${NODE_ENV:=production} node start-app.js\"
this is how I did it, first you need to install two dev-dependencies
https://www.npmjs.com/package/env-cmd this load your env var from your file
https://www.npmjs.com/package/cross-env this use environment variable in script
example scripts:
"env-cmd ./.config/prod.env cross-env-shell \"docker volume create $DOCKER_VOLUME\""
this load $DOCKER_VOLUME env var from prod.env
update: starting from env-cmd version 10, you need specify -f flag if you want to use a custom env file path
"env-cmd -f ./.config/prod.env cross-env-shell \"docker volume create $DOCKER_VOLUME\""