Based on classnames-loader, this webpack loader is made to fix an issue related to next. Depending where you created folder inside next e.g. src/components, src/pages/home/components, the classnames-loader won't get the same absolute path and will fail to load classnames/bind.
Thanks to @itsmepetrov for the original classnames-loader, checkout the original readme for details and examples.
npm install next-classnames-loader -ED