there is concatenated module in webpack https://github.com/webpack/webpack/blob/main/lib/optimize/ConcatenatedModule.js codeGeneration method generates code.. but without reducing your issue to reproducible repo hard to guess..

@vankop Is it a good approach to use optimization.concatenateModules: false?

this will increase your output size. if it is ok for you, you can use it.

Had the same issue after a recent upgrade to Webpack 5. To reiterate @bmarti44's point (or, at least, what I think might be the issue):

If you have the ModuleConcantenationPlugin included in your webpack config's plugin section like this:

new webpack.optimize.ModuleConcatenationPlugin()

and that same config has mode set to production, then I believe this issue might occur, since according to the documentation: "By default this plugin is already enabled in production mode and disabled otherwise." It does seem a little odd that this would be the case, but removing the plugin instantiation fixed things.

Would it be possible to add this detail to the documentation (either here or in the Webpack 5 upgrade docs)? I'd be happy to do so if it's easier

@EvanSanderson Feel free to do it