fix(ws): remove all frame listeners on client closure

[kettanaito]

Makes sure that WebSocket frames also remove all their listeners on connection closure.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: ea15cdcd-8d72-4c41-a163-14a6f9ad7045

📥 Commits

Reviewing files that changed from the base of the PR and between d697485 and a351553.

📒 Files selected for processing (1)

• src/core/experimental/sources/interceptor-source.ts

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📝 Walkthrough

Walkthrough

The PR adds resource cleanup logic to the WebSocket interceptor source. When a WebSocket client connection closes, the frame now removes all its registered event listeners, preventing listener leakage after disconnection. This mirrors existing cleanup behavior in the HTTP response handler.

Changes

WebSocket Connection Cleanup

Layer / File(s)	Summary
WebSocket Cleanup Implementation src/core/experimental/sources/interceptor-source.ts	Registers a one-time close listener on the WebSocket client to call removeAllListeners() when the client disconnects, preventing orphaned event listeners.

Possibly Related PRs

• mswjs/msw#2737: Related cleanup work in the same file—both PRs ensure frame event listeners are removed to prevent listener retention, with this PR adding WebSocket connection close cleanup.

Estimated Code Review Effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

🐰 When sockets close their sleepy eyes,
The listeners fade away and rise—
No lingering ghosts of events past,
Just cleanup magic, clean and fast!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: adding cleanup of frame listeners when WebSocket clients disconnect, which matches the changeset.
Description check	✅ Passed	The description is directly related to the changeset, explaining that WebSocket frames now remove listeners on connection closure.
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.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/ws-listener-cleanup

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/msw@2739

commit: af2dac4

[kettanaito]

Released: v2.14.5 🎉

This has been released in v2.14.5.

• 📄 Release notes
• 📦 View on npm

Get these changes by running the following command:

npm i msw@latest

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