Document subtle CORS middleware allowedHeaders behavior #5936
+55
−0
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Add comprehensive JSDoc documentation to HttpMiddleware.cors explaining the important but subtle behavior of the allowedHeaders option: - When empty array (default): reflects client's Access-Control-Request-Headers (permissive - allows all headers) - When non-empty array: only allows specified headers (restrictive) This clarifies the default behavior which was previously undocumented and could lead to confusion when working with CORS requests, especially for tracing headers like traceparent and b3. Includes practical examples showing different usage patterns. Fixes #5935 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
🦋 Changeset detectedLatest commit: 2ea374c The changes in this PR will be included in the next version bump. This PR includes changesets to release 31 packages
Not sure what this means? Click here to learn what changesets are. Click here if you're a maintainer who wants to add another changeset to this PR |
tim-smart
approved these changes
Dec 29, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
Added comprehensive JSDoc documentation to
HttpMiddleware.corsexplaining the subtle but important behavior of theallowedHeadersoption: when empty array (default), it reflects back the client'sAccess-Control-Request-Headers(permissive), and when non-empty array, only specified headers are allowed (restrictive).Test plan
Fixes #5935