Unable to build with webpack in prod mode

[tollr]

Hello,

I'm currently having trouble with this plugin, which is great btw, now that we are a trying to move to awebpack builder with Symfony Encore.

The problem is, I can't seem to build in prod while there is no problem in dev or with the webpack dev server.

[EDIT] I'm really sorry, I was sure it wasn't working, but it seems to now work fine ? I still get the error though. Really not sure about what is going on here.

The error code is the following :

I've been doing research about this error. Uglify.js don't work with ES6 syntax, so it might be the problem.

The initialization of the plugin is done this way :

My package.json :

Do tell me if you need more informations.

Thanks for your work, we've been using this plugin from the CDN for a while it's always been working great.

Many thanks.