jsdom: localStorage implementation can't be spied on. webidl converter issue?

Basic info:

• Node.js version: v9.11.2
• jsdom version: 11.12.0

Minimal reproduction case

In the latest release 11.12.0 jsdom implemented localStorage and sessionStorage support. That’s really awesome and great but the issue I am experiencing is that we can’t spy On it or mock it during testing with jest.

I’ve created a simple repo for the use case at: https://github.com/vlad0/jest-localstorage-issue

As much as I hate to do this but I’d like to give a link to the jest issue I’ve created https://github.com/facebook/jest/issues/6798

and mainly because of the setter implementation(webidl I guess):

What I have discovered is that in ./node_modules/jsdom/lib/jsdom/living/generated/Storage.js the issue is with the set method of the Proxy

Currently the code below is on line 278.

if (ownDesc === undefined) {
          const parent = Reflect.getPrototypeOf(target);
          if (parent !== null) {
            return Reflect.set(parent, P, V, receiver);
          }
          ownDesc = { writable: true, enumerable: true, configurable: true, value: undefined };
        }

if we remove receiver from return Reflect.set(parent, P, V, receiver); we will be able to spy on it. But I guess that's coming from webidl converter

How does similar code behave in browsers?

(Link to a jsbin or similar suggested.)