So I recently attended a talk by webpack's Juho Vepsäläinen and found the answer in this slide:
{
test: /.css$/,
oneOf: [
{
resourceQuery: /inline/, // foo.css?inline
use: 'url-loader',
},
{
resourceQuery: /external/, // foo.css?external
use: 'file-loader',
},
],
}
resourceQuery to the rescue!