refactor(plexus): migrate MeasurableNodes to functional component

[hharshhsaini]

Which problem is this PR solving?

• Resolves [UI Refactor] [plexus] Migrate MeasurableNodes to Functional Component #3390

Description of the changes

• Migrated the MeasurableNodes component from a class-based component to a functional component with React.memo()
• Converted MeasurableNodes class component extending React.Component to a functional component
• Converted shouldComponentUpdate to custom areEqual comparison function for React.memo()
• Destructured props directly in the function signature
• Removed the render() method and converted to direct return statement
• Maintained generic type support using double type assertion pattern: as unknown as <T = {}>(props: TProps<T>) => React.ReactElement[]
• Preserved all existing functionality including custom update logic with isSamePropSetter
• No changes to component logic or behavior, only structural refactoring

How was this change tested?

• All existing plexus tests pass (18 tests)
• Build successful for plexus package
• Prettier formatting verified
• Minimal diff: 36 insertions, 41 deletions

Test proof -

Before

After

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/main/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully: make lint test

AI Usage in this PR (choose one)

See AI Usage Policy.

• None: No AI tools were used in creating this PR
• Light: AI provided minor assistance (formatting, simple suggestions)
• Moderate: AI helped with code generation or debugging specific parts
• Heavy: AI generated most or all of the code changes

[github-actions]

Hi @hharshhsaini, thanks for your contribution! To ensure quality reviews, we limit how many concurrent open PRs new contributors can open.

This PR is currently on hold (Status: 10/1 open). We will automatically move this into the review queue once your existing PRs are merged or closed.

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[Copilot]

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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[jkowall]

@hharshhsaini please address copilot comments

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.98%. Comparing base (42b5388) to head (51f4020).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3533      +/-   ##
==========================================
+ Coverage   88.68%   88.98%   +0.30%     
==========================================
  Files         300      300              
  Lines        9560     9559       -1     
  Branches     2445     2536      +91     
==========================================
+ Hits         8478     8506      +28     
+ Misses       1078     1050      -28     
+ Partials        4        3       -1     

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[hharshhsaini]

@jkowall @yurishkuro The Copilot feedback on the default export double type assertion has been resolved. The signature has been casted directly to as unknown as typeof MeasurableNodes to preserve generic type consistency with other memoized components in this package like MeasurableNodesLayer and HtmlLayersGroup.

The PR is fully ready for final review and merge.

[jkowall]

Thanks for the contribution @hharshhsaini!

The refactoring logic looks correct — the shouldComponentUpdate → areEqual inversion is properly done and isSamePropSetter is preserved. A couple of things to address before this can be merged:

1. Export type assertion inconsistency: The current diff still uses the explicit type assertion (as unknown as <T = {}>(props: TProps<T>) => React.ReactElement[]). I see you mentioned switching to as unknown as typeof MeasurableNodes, but the diff doesn't reflect that change yet. Every other migrated component in this package (HtmlLayer, HtmlLayersGroup, MeasurableNodesLayer, NodesLayer, SvgEdge, SvgDefEntry, SvgEdgesLayer, SvgLayer, SvgLayersGroup) uses as typeof ComponentName — please update to match.

2. Test coverage: Codecov reports 26.67% patch coverage with 11 missing lines. It would be good to add basic tests for the areEqual comparator to verify the component skips re-render with identical props and re-renders when props change.

3. Rebase needed: The branch is 26 commits behind main — please rebase onto the latest main.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

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[hharshhsaini]

@yurishkuro @jkowall The areEqual test has been thoroughly refactored based on Copilot's valuable feedback. Instead of hacking into the internal .compare property, the areEqual comparator is now cleanly exported and tested directly in isolation.

The misleading comment about isSamePropSetter identity comparisons has also been removed. Coverage for MeasurableNodes.tsx is completely retained at 100%.

[jkowall]

Thanks for the contribution and addressing the comments.