Found a question that looks similar to the one you've asked about and it has this answer as the accepted answer

If you do not understand how to apply any code from npmjs.com website, click on the repository GitHub link on the right-hand side and check for folders like Test or Examples. You will get a brief idea of how to work and where to apply the given codes. You will have several examples there.

Check the below URL, this might help you. this link is from the same Github Test folder. https://github.com/quackes/webpack-encoding-plugin/blob/master/test/tests.js