jest.useFakeTimers("modern") overrides performance object

[Smrtnyk]

🐛 Bug Report

in setupFilesAfterEnv I have added a timing object to window.performance because I have a logic that relies on those values

When I use jest.useFakeTimers("modern") performance object is overriden and timing object does not exist on it anymore

I could do the initialization logic first and then activate jest.useFakeTimers("modern") but my init logic is a bit complex and it saves references to setTimeout and some other stuff which would result in original setTimeout called when I defer something in my logic and not the faked ones.

To Reproduce

Steps to reproduce the behavior:

Assign some value to performance.timing.
Call jest.useFakeTimers("modern").
Do some logic with performance.timing

Expected behavior

I would expect to still see the timing object as that is what I prepared in my setupFilesAfterEnv file.

envinfo

System:
OS: Windows 10 10.0.19042
CPU: (12) x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz
Binaries:
Node: 14.15.1 - C:\Program Files\nodejs\node.EXE
npm: 6.14.8 - C:\Program Files\nodejs\npm.CMD
npmPackages:
jest: 26.6.3 => 26.6.3

[SimenB]

Can you report this to @sinonjs/fake-timers? Seems to me like some of the installation logic is faulty (i.e. overriding): https://github.com/sinonjs/fake-timers/blob/07d90ce136c2e16c488782c64aab14fbdcde9329/src/fake-timers-src.js#L1279-L1300

The "only" thing we do in Jest is call install: https://github.com/facebook/jest/blob/b86e48a2d0ab7afe09cfb133f0dccc2ca5fac0b3/packages/jest-fake-timers/src/modernFakeTimers.ts#L102

[github-actions]

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