Does not work when loaded as an ESM module

[kirlat]

The plugin works great when loaded as require('clean-webpack-plugin'). However, we need to run it in a node.js build script that uses an ESM import syntax, with --experimental-modules flag (node.js 10). This is how we load it: import CleanWebpackPlugin from 'clean-webpack-plugin'. Unfortunately, it returns the following error: TypeError: Cannot read property 'filename' of undefined. I've checked the plugin code, and the only place where filename is used is module.parent.filename. I checked, and module.parent is undefined when plugin is loaded using ESM syntax.

What would be the best way to fix this? It seems that module.parent.filename is used to determine Webpack location. However, plugin takes a root option that is a Webpack root path. Can we check if module.parent is undefined and if it is, use a root option instead of it?

This plugin is really helpful and I would love to be able to use it in an ESM environment.

[i8degrees]

Hi, I just wanted to throw it out there that I suffer the same problem as @kirlat above. I use @std/esm for an ESM environment and decided to take a stab at resolving the issue with using the suggestion made. I forget now why exactly I was not able to pass the existing root option as-is, so I added an additional option under the name of context.

new CleanWebpackPlugin(['dist'], {
      root: __dirname,
      context: __dirname,
    })

I have been using this successfully for the past few months now without hiccup. Here's to hoping that somebody with more time might be able to nail this problem in its coffin! :-)

Thanks!

[riri]

I got exactly the same problem than @kirlat, using ESM, TypeError: Cannot read property 'filename' of undefined, as module.parent is undefined.

[MeiKatz]

I am having the same problem currently and I think the solution is to make the check against module.parent conditionally: if it is not defined then webpackDir should be undefined.

webpackDir = module.parent && path.dirname(module.parent.filename);

And so the problem is solved.

[chrisblossom]

Closed via #95 for ^1.0.0.

v2.0.0 via #99 has been released. See johnagan/clean-webpack-plugin#usage. Please open a new issue if you continue to have problems.