Babel doesn't work with IE11 on built in class Map extending

Question

I have some legacy code, a class ExtraMap that extends built-in Map class.

export class ExtraMap<K, V> extends Map<K, V> {
    getOr(key: K, or: OrFunctionType = defaultOrFunction): V {
        const value = this.get(key);
        return !!value ? value : or(key);
    }
}

In IE11 I am getting this error: Object doesn't support property or method 'getOr'

Babel version is 7, but whatever I tried it just doesn't seem to work out.

I have tried plugin-transform-classes and plugin-proposal-class-properties, even babel-plugin-transform-builtin-extend, but nothing helped.

Here is whole .babelrc config:

{
    "presets": [
        "@babel/preset-env",
        "@babel/preset-react"
    ],
    "plugins": [
        "@babel/plugin-proposal-class-properties",
        "@babel/plugin-transform-classes",
        "@babel/plugin-proposal-optional-chaining"
    ]
}

Any ideas?