window.performance.getEntriesByType unit test with jasmine

Question

I have a function in my Angular service that does a "this.window.performance.getEntriesByType('navigation')".

But I can't mock it.

Here is my service.spec.ts :

    const mockWindowService = jasmine.createSpyObj('WINDOW_TOKEN', ['performance']);
    Object.defineProperty(mockWindowService, 'performance', {
        value: {
            getEntriesByType: { windowPerformanceFixture },
        },
    });

    TestBed.configureTestingModule({
        imports: [HttpClientTestingModule],
        providers: [
            { provide: WINDOW_TOKEN, useValue: mockWindowService },
        ],
    });

// My windowPerformanceFixture object is in an external file

here is the error I receive :

TypeError: performance.getEntriesByType is not a function

Do you know how to mock this ?