Show additional error properties in toThrow diff view #8697

Describe the bug

Problem

In Vitest 3, the toThrow / toThrowError matcher now compares both the error instance and its properties. However, if the error instance and the error message are the same, but some random property differs, the extension reports a failure without showing the diff. Instead, I have to manually log the error object to understand what’s different.

Suggested Improvement

It would be very helpful if the diff view could also display the additional properties of the error instance, so the mismatch is immediately visible in the test output

Benefit

Including the additional properties in the diff would make debugging faster and reduce the need for manual logging.

🙏 Thanks for considering this improvement and making this great extension!

Reproduction

expect(() => {
  throw Object.assign(new Error("Something went wrong"), { code: 123 });
}).toThrow(new Error("Something went wrong")); 
// fails, but the diff does not show the extra `code` property

became

Output

No visible diff in the UI (see the screenshot above)

Extension Version

1.28.2

Vitest Version

3.2.4

Validations

• Check that you are using the latest version of the extension
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.