fix(screencast): deliver frames without CDP timestamp

[Kikobeats]

Summary

• Release on master failed twice because @browserless/screencast capture frames asserted frames.length > 0 and got zero frames (unrelated to fix(function): resolve nodePaths under an isolated store #875).
• CDP marks ScreencastFrameMetadata.timestamp as optional; the handler dropped those frames, so capture looked empty under GL/xvfb.
• Fill a wall-clock timestamp fallback, harden the integration test with a local CSS-animated page, and add a unit test for omitted timestamps.

Test plan

• pnpm --filter @browserless/screencast test (11 passed)
• CI matrix + release recursive test green

Made with Cursor

Summary by CodeRabbit

• Bug Fixes

  • Screencast frames without timestamps are now delivered with a generated timestamp when frame handling is enabled.
  • Frames without a handler continue to be acknowledged and skipped correctly.

• Tests

  • Improved frame-capture coverage, including validation for timestamp-less frames.
  • Updated animation testing for more reliable results.

[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: 09a9c469-f338-4b56-9e00-430d1de7c398

📥 Commits

Reviewing files that changed from the base of the PR and between 6308f0d and e0a85b8.

📒 Files selected for processing (2)

• packages/screencast/src/index.js
• packages/screencast/test/index.js

---

📝 Walkthrough

Walkthrough

The screencast handler now delivers frames without timestamps by generating a wall-clock timestamp. Tests use local animation and verify frame delivery, metadata preservation, timestamp generation, and CDP acknowledgement.

Changes

Screencast frame normalization

Layer / File(s)	Summary
Timestamp fallback handling packages/screencast/src/index.js	onScreencastFrame defaults missing metadata and generates a timestamp when CDP omits one. Frames without a callback remain acknowledged and skipped.
Timestamp fallback coverage packages/screencast/test/index.js	The capture test uses local animated content. Added coverage verifies delivery, metadata preservation, generated timestamps, and acknowledgement for frames without timestamps.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 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 clearly and concisely describes the fix for delivering screencast frames without a CDP timestamp.
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

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/screencast-capture-frames

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coveralls]

coverage: 80.68% (+0.03%) from 80.653% — fix/screencast-capture-frames into master