fix: add rss+xml to textTypes, fix isJSONSerializable(null)

[marceli1404]

Changes

#597 — RSS feeds with application/rss+xml (and application/atom+xml) returned as Blob instead of text. Added both to the textTypes set so detectResponseType returns "text".

#571 — isJSONSerializable(null) threw Cannot read properties of null (reading 'buffer') because typeof null === 'object', so null passed the type checks and crashed at value.buffer. Added an explicit value === null guard returning true (null is JSON-serializable).

Tests

All 28 existing tests pass.

Summary by CodeRabbit

• Bug Fixes
  • Correctly recognizes null values as JSON-serializable.
  • Properly handles RSS and Atom feed responses as text instead of binary content.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 1c0b3864-f38f-4699-ab31-f1dbb0046ff5

📥 Commits

Reviewing files that changed from the base of the PR and between 1dbc37f and 6207f96.

📒 Files selected for processing (1)

• src/utils.ts

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📝 Walkthrough

Walkthrough

The utility updates mark null as JSON-serializable and classify RSS and Atom XML MIME types as text responses.

Changes

Utility behavior

Layer / File(s)	Summary
Null JSON serialization handling src/utils.ts	isJSONSerializable now explicitly accepts null.
RSS and Atom response classification src/utils.ts	detectResponseType now classifies application/rss+xml and application/atom+xml as "text".

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• unjs/ofetch#612: Updates detectResponseType handling for XML content types.
• unjs/ofetch#616: Updates XML-based content type classification in detectResponseType.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title matches the main changes: expanding textTypes for RSS and fixing null handling in isJSONSerializable.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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