Do you want to request a feature or report a bug?
What is the current behavior?
sideEffects: false is (or will be, in webpack 4) a library-level setting.
If the current behavior is a bug, please provide the steps to reproduce.
What is the expected behavior?
If this is a feature request, what is motivation or use case for changing the behavior?
It would be incredibly useful to have a way for app authors to opt libraries into this behavior, possibly for cases where library authors never added this setting themselves, for whatever reason.
Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.