Is node-sass a dev or a production dependency on React projects?
Since it's required to do a production build, it should be in the production dependencies list imho.
In my experience, most of the time the project gets build afresh for production, so needs all the packages required to build from scratch.
A dev dependency might something like webpack-dev-server which isn't needed for a prod build, but clearly is used in development (assuming one is using it).