Problem

webpack is mangling class names.

export class Test {
    constructor() {
        this.test = 1;
    }
}

Test.name; // should be "Test", but is instead some mangled character like "n"
Test.prototype.constructor.name; // similar to above

Test this out with

npm run start

And use console to evaluate the expressions on the lib library.

Solution

The current webpack configuration solves this issue by explicitly keeping function and class names:

    optimization: {
        minimizer: [
            new UglifyJSPlugin({
                cache        : true,
                parallel     : true,
                uglifyOptions: {
                    compress: true,
                    ecma    : 6,
                    keep_fnames: true,
                    keep_classnames: true,
                },
                sourceMap    : true
            })

        ]
    },

Although UglifyJS only works on ES5, so we have to pull in Babel as well:

    module      : {
        rules: [
            {
                test   : /\.js$/,
                include: [/src/],
                use    : {
                    loader : 'babel-loader',
                    options: {
                        presets: ['@babel/preset-env']
                    }
                }
            },
        ]
    },