Response.body with jest-express

When using package jest-express to mock Requests in a Typescript project, what is the correct way to ensure that req.body is an object and not a string?

When a requests's body is parsed to JSON with express.json(), the value of req.body is replaced with the parsed Javascript object, but the Request type from jest-express has string as the type of the body property.

Is there some Typescript way of 'changing' the type?

How to get the Request type from jest-express to have a body property of type any or object?

Bonus question:

The Request type from jest-express does not seem to be a direct replacement for Request from express. I have to do something like this:

middlewareFn(<express.Request> <unknown> request, <express.Response> <unknown> response)

to cast from the jest-express types to the express types when using the jest-express mocks as arguments in the tested functions.

How to use jest-express types as direct replacements for express types?