How to correctly export aggregated javascript classes

I'm using VSCode 1.41.1 (November 2019 release). I have some JavaScript classes in a folder like so:

a.js

class A {
    constructor() {
        this.m = 2;
    }
}

export default A;

b.js

class B {
    constructor() {
        this.n = 4;
    }
}

export default B;

I am trying to gather them into a single library so that I can do something like Lib.A to refer to the A class.

My current method is this:

lib.js

import A from './a';
import B from './b';

class Lib {};

Lib.A = A;
Lib.B = B;

export default Lib;

I then would like to use the Lib class in an external app. I have this file:

app.js

import Lib from './lib';

/**
 * @param {Lib.A} a
 * @param {Lib.B} b
 */
function foo(a, b) {
}

However, when I mouse over the params a or b, the tool tips say (parameter) a: typeof A and (parameter) b: typeof B, respectively, and not (parameter) a: A and (parameter) b: B like I would expect. Additionally, the auto-completion when I do a. shows the A class properties, and not an instance of A (with the m member), just like the tool tips imply.

I have a more complex project whose import/export code hasn't changed, and this behavior didn't exist in it a few months ago. It seems like a VSCode update perhaps?

Or maybe I'm not combining the A and B classes or exporting the Lib class correctly? Or maybe the JSDoc that I'm using has changed how param typing is declared?

Thank you for any help you can give.

Edit: I've also tried for the Lib export:

const Lib = {
    A,
    B
};

But this makes the VSCode Intellisense for the foo function parameters just show any as their type.

Also, I see that just doing:

const a = new Lib.A();

The intellisense does correctly make the variable a as a type A. So perhaps I'm just doing the JSDoc @param declaration wrong?