I script it that way and then add a makefile on top of it so that it's conventional and handles things like envvar setting.

    build:
        NODE_ENV=production yarn build:server
        NODE_ENV=production yarn build:client

    test:
        NODE_ENV=test yarn test

we do the same, but the npm scripts are just the "entry point". one of them was this:

    "build:dist": "NODE_ENV=production babel ./src --out-dir ./dist"

Maybe you missed this paragraph, it talks about your point:

Makefiles are more versatile