Do you want to request a feature or report a bug?
What is the current behavior?
When inheriting from a base webpack config provided by an npm module and merging via webpack-merge, ModuleConcatenation fails to properly concatenate, giving the bailout warning ‘Module is not an ECMAScript module’ (despite the fact all files are indeed ECMAScript modules).
If the current behavior is a bug, please provide the steps to reproduce.
Created a simple repro repo here: https://github.com/jdb8/webpack-module-concat-repro. Instructions are detailed in README.md.
What is the expected behavior?
The output bundle should successfully concatenate the module with
ModuleConcatenationPlugin. It shouldn’t matter whether the plugin is defined in the base or child config, or whether the base config is exported from an npm module.
If this is a feature request, what is motivation or use case for changing the behavior?
Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.