jest.fn() inside jest.mock() returns undefined

I'm having a simple "util" module with a default export and 2 named exports.

const foo = () => 'foo'
export default foo
    
export const bar = () => 'bar'
export const baz = () => 'baz'

on my test, I'm mocking it like that :

jest.mock('./util', () => ({
  __esModule: true,
  default: jest.fn(() => 'mocked foo'),
  bar: jest.fn(() => 'mocked bar'),
  baz: jest.fn(() => 'mocked baz'),
}))

describe('util', () => {
  //...
})

On my component, when I call foo(), bar() or baz(), I received undefined. but everything is working if I remove jest.fn() like that :

jest.mock('./util', () => ({
  __esModule: true,
  default: () => 'mocked foo',
  bar: () => 'mocked bar',
  baz: () => 'mocked baz',
}))

My example is very close to the one on jest doc : https://jestjs.io/docs/mock-functions#mocking-partials

I'm using React (CRA) and TypeScript

I know there is different ways to mock a module but I'm curious to understand the issue that I'm facing.

any idea what I'm doing wrong ? :) Thanks !