How should `shouldAdvanceTime` work together with `Date`?

[sokyrynskyi]

• FakeTimers version : 11.1.0
• Environment : MacOS 13.5.2, NodeJS v18.17.0
• Example URL : -
• Other libraries you are using: -

What did you expect to happen?

Each time new Date() is called -- the value is advanced according to the config.

What actually happens

The value is always the same.

How to reproduce

it('should advance Date', function() {
  const clock = FakeTimers.install({
      now: new Date('2022-02-02 22:22:22').getTime(),
      shouldAdvanceTime: true,
      advanceTimeDelta: 1000,
      toFake: ['Date'],
  });

  console.log('Date1: ', new Date()); // Actual output 'Date1:  2022-02-02T22:22:22.000Z'
  console.log('Date2: ', new Date()); // Actual output 'Date2:  2022-02-02T22:22:22.000Z'

  clock.uninstall();
});

[fatso83]

Hi, @sokyrynskyi! AFAIK, there is nothing in the docs that says creating a new date instance should advance time.

tells lolex to increment mocked time automatically based on the real system time shift

To be honest, that would be quite contra-intuitive, as you can create several hundred thousands of date instance per second, so deciding what should the granularity be would be a task upon itself.

You can see examples of how this is being used in the docs.