jest.mock of ESM should fail, and it's correct

[kdy1]

This is not an issue, because the input was already wrong.

If you really want to workaround this, see #5151 (comment)
Note that this is not an official one, and it will break frequently.

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jest not working with ESM is not an issue of swc. See jestjs/jest#9430

common js vs ESM behavior

Technically this can be workarounded by SWC by compiling in a wrong way.

But ESM is an established standard, and swc follows the specification. If you use ESM as input, swc will compile the code to behave in a way defined by the specification.

You may claim the official typescript compiler does not follow specification if module type is common js, but it's a bug of tsc. If you want behavior of common js, you can write a common js module instead.

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Discussions

• transformed `CJS` compatibility with jest #5151

Issues

• jest.spyOn does not work when compared ts-jest #3843
• @swc/jest does not support jest mocking of exported functions within same module #4455
• Cannot redefine property error when using jest.spyOn after v1.2.206 #5059
• 205 to 206 update breaks jest tests with star imports #5204

[kwonoj]

For the opinions / suggestions, please use general discussions #5151.

For the workaround, please refer #5151 (comment) .

This issue itself is an announcement, will be locked to avoid diverging comments between existing discussions.

[kdy1]

Closing in favor of #7435