Jest: Add "clearAllMocks" method that will run "mockClear" on all mocks

[olmg-justin-ligman]

Do you want to request a feature or report a bug?
feature

What is the current behavior?
Currently, there is no way to clear all mocks at once. There used to be a method called jest.clearAllMocks, but it was actually just resetting all the mocks, and appears to have been replaced with jest.resetAllMocks in 17.0.0 (https://github.com/facebook/jest/blob/224491bf9a51834c2d348e2d0c81b3b970150bd4/CHANGELOG.md).

The problem with resetting all mocks is that it also replaces the implementations that you set on the mock, so you can't call it before/after tests if other tests rely on those implementations. Because of this, you have to call myMock.mockClear() on every mock between tests, which will only reset the calling information.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal repository on GitHub that we can npm install and npm test.
N/A

What is the expected behavior?

Since Jest supports both myMock.mockReset() and myMock.mockClear(), it would make sense that there would be an equivalent for clearing all mocks, since there is one for reseting them.

Run Jest again with --debug and provide the full configuration it prints. Please mention your node and npm version and operating system.
N/A

[acateland]

jest 17 broke many of my tests, the following worked on jest 16.0.2 with clearAllMocks
https://github.com/acateland/jest-mock-issue
So i guess clearAllMocks was not just renamed

The above workaround consisting of reseting mock manually doesn't apply to mocked modules

[cpojer]

This has come up a few times. I think we need to bring clearAllMocks back. cc @mrsharpoblunto

[jorilallo]

Would this also affect timer mocks? I ran into issues where after upgrading to 17 jest.runAllTimers() wouldn't run setTimeouts when I run resetAllMocks on beforeEach block. Same code worked with Jest 16 and clearAllMocks.

[niksajanjic]

It also makes sense to add _clearMocks_ boolean flag as part of Jest configuration, similar to _resetMocks_ flag that already exists.

[vkrol]

We cannot upgrade to Jest 17 because of this :(

[jdmunro]

This caused me a bit of head scratching today. I mistakenly got the impression from the release notes that resetAllMocks was a 1:1 replacement for clearAllMocks. I see that's not the case - clearAllMocks is actually what I'm looking for.

The differences between these are slightly tricky:

mockClear: resets call counts etc.
mockReset: resets all information stored in the mock

Maybe mockClear could be more explicitly named, e.g mockResetCalls or something better. Or maybe mockReset({callsOnly: true}) and resetAllMocks({callsOnly: true})

Sorry I don't have a better suggestion at this stage ☹️

[cpojer]

@jdmunro I'm ok with a PR that brings back clearAllMocks alongside resetAllMocks.

[thymikee]

Closed via https://github.com/facebook/jest/pull/2771