webpack terser minify imported library

Question

I'm using webpack for an internal project. The project is set to be minified with TerserPlugin. The project also uses paper js library to deal with some SVG transformations. The issue I have is when I build the project for production, all paper usages are minified as well. I use the following configuration in webpack config plugins:

    new TerserPlugin({
        minify: TerserPlugin.terserMinify,
        terserOptions: {
            mangle: {
                properties: {
                    regex: /^[^_]/,
                    reserved: ['HttpRequest', 'EditorContainer', 'Color', 'paper']
                },
                reserved: ['paper']
            }
        }
    })

In the project I have the following code:

paper.setup(new paper.Size(this.canvas.width, this.canvas.height));

In the production build I get the following minified code:

Le().sC(new(Le().yg)(this.canvas.width,this.canvas.height))

At runtime I get the Le().yg is not a constructor error. Is it possible to configure Terser to leave all paper related code unchanged and only mangle internal properties, functions etc?