fix(5k webinar) - remove js error

[mickelr]

COMPLETES #< INSERT LINK TO ISSUE >

This pull request addresses

A TypeError in the Mercury WebSocket message handler (_onmessage) that occurs when processing messages without an eventType property in their data payload. In large webinar scenarios (5k+ participants), Mercury can receive WebSocket messages (e.g., subscription responses, control messages) that lack the standard data.eventType field. When this happens, _getEventHandlers(data.eventType) is called with undefined, which then throws a TypeError on eventType.split('.'). This crashes the message processing pipeline and causes a hard JS error at runtime.

by making the following changes

• Guard in _getEventHandlers(eventType) (internal-plugin-mercury/src/mercury.js): Added an early return of [] when eventType is falsy (undefined, null, or empty string), preventing a TypeError on .split().
• Guard in _onmessage() (internal-plugin-mercury/src/mercury.js): Added a null check before calling _getEventHandlers() — if data is missing or data.eventType is not present, the message is emitted as a generic 'event' and processing returns early instead of crashing.
• Unit tests (internal-plugin-mercury/test/unit/spec/mercury.js): Added test coverage for:
  • _onmessage() with undefined data, missing eventType, and subscription-style responses
  • _onmessage() still correctly processes messages with a valid eventType
  • _getEventHandlers() with undefined, null, empty string, and unregistered namespace inputs
• Reverted docs/samples/meetings.min.js: Rolled back an accidental rebuild of the sample bundle that introduced a broken version header (vundefined) and content changes unrelated to this fix.

Change Type

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Tooling change
• Internal code refactor

The following scenarios were tested

• Unit tests: Added and ran tests for _onmessage() with missing data/eventType and _getEventHandlers() with falsy inputs — all pass.
• Regression: Verified that messages with a valid eventType (e.g., conversation.activity) still route through the normal event handler pipeline.
• Syntax validation: Confirmed docs/samples/meetings.min.js parses cleanly after rollback (node --check passes).

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• GAI was not used (or, no additional notation is required)
• Code was generated entirely by GAI
• GAI was used to create a draft that was subsequently customized or modified
• Coder created a draft manually that was non-substantively modified by GAI (e.g., refactoring was performed by GAI on manually written code)
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  • Github Copilot
  • Other - Please Specify
• This PR is related to
  • Feature
  • Defect fix
  • Tech Debt
  • Automation

I certified that

• I have read and followed contributing guidelines
• I discussed changes with code owners prior to submitting this pull request
• I have not skipped any automated checks
• All existing and new tests passed
• I have updated the documentation accordingly

---

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[chatgpt-codex-connector]

💡 Codex Review

https://github.com/webex/webex-js-sdk/blob/fa258a6c2de92c05be68a6a59ee0fcfa700875ca/docs/samples/meetings.min.js#L2
Restore valid JavaScript in meetings.min.js bundle

The updated docs/samples/meetings.min.js is syntactically invalid and will fail to load in browsers/Node (node --check docs/samples/meetings.min.js now reports SyntaxError: Unexpected token ';'), while the parent version parses cleanly. This means the sample app script is broken at runtime, so users opening the meetings sample will hit a hard JS parse error before any SDK logic can run.

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Reviewed commit: 1e807ba3c8

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[chatgpt-codex-connector]

Await _onmessage before asserting valid eventType behavior

_onmessage() processes normal events asynchronously (the event emit happens in a .then(...)), but this test calls it and immediately runs assert.neverCalledWith(...). That means the assertion executes before async emits occur, so the test can pass even if valid eventType handling regresses (including the exact call this assertion is trying to reason about). This leaves the new guard path effectively unverified for the non-early-return case.

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