Converting from Custom Webpack Config to Rails Webpacker Config

  1. Compare your package.json and the dependencies in https://github.com/rails/webpacker/blob/master/package.json#L14-L48 and avoid any duplicates. We don't want different versions of the same packages. We want the versions from rails/webpacker unless we specifically want to override them.
  2. Search the rails/webpacker repo for anything you're not sure about in terms of package names.
  3. run bin/webpack and make sure there are zero errors
  4. update webpack plugins and loaders to current or close to current
  5. Make sure that your bin/webpack and bin/webpacker match the latest on https://github.com/rails/webpacker/tree/master/lib/install/bin