I am not 100% sure my terminology is right here, but what I want to do is as follows. I managed to successfully mock stripe.customers.create by creating a manual mock like this:

__mocks__/stripe.js 

class Stripe {}
const stripe = jest.fn(() => new Stripe()); 
module.exports = stripe;
module.exports.Stripe = Stripe;

then in my unit.test.js I import the mock like this

const { Stripe } = require("stripe");
Stripe.prototype.customers = {
  create: jest.fn(() => {
    return {
      id: "cus_testid",
    };
  }),
};

And the stripe.customers.create() method is mocked just fine. However, the problem starts when I start to (for the lack of better word) "nest" or "chain" the methods further down the stripe object. For example this mock will not work:

Stripe.prototype.checkout.sessions = {
  create: jest.fn(() => {
    return {
      session: {
        url: 'someurl'
      }
    }
  })
}

TypeError: Cannot set property 'sessions' of undefined

Why can't I set up such a nested method mock and how should I approach doing such a nested mock? Should I modify the manual mock to accomplish this?