Improve PercentileLineChart perf (and thus Summary page) by over 20x

[sean-zlai]

Summary

By extracting series from the markup (which made it reactive) and intentionally NOT using $derived, rendering performance of PercentileLineChart improved by over 20x (>1100ms down to <50ms).

This makes navigating to the Summary tab MUCH better (before we would sometimes hit the browser "Are you sure you want to wait" prompts).

$state.opaque() runes was being considered that could have helped here, but it was decided to not be the right abstraction. (I'm waiting on a solution to fix LayerChart's force simulations that have a perf regression in Svelte 5 due to granular reactivity / proxy creation)

Before

CleanShot.2025-03-05.at.15.03.33-converted.mp4

After

CleanShot.2025-03-05.at.15.09.37-converted.mp4

Checklist

• Added Unit Tests
• Covered by existing CI
• Integration tested
• Documentation update

Summary by CodeRabbit

• Refactor
  • Optimized the chart component's data handling to improve performance and overall clarity.
  • Adjusted the internal structure by moving data definitions outside inline usage and refining type specifications for better consistency.

[coderabbitai]

Walkthrough

The PercentileLineChart.svelte component has been updated to enhance data handling and performance. Changes include a revised import statement for ComponentProps, the extraction of the inline series definition to a constant variable, an explicit type definition for the data array's mapped values, and passing the series constant as a prop to the LineChart.

Changes

File Path	Change Summary
frontend/src/lib/.../charts/PercentileLineChart.svelte	Updated import syntax; extracted inline series to a constant; added explicit type to mapped data values; passed series as prop.

Possibly related PRs

• Update LayerChart to 1.0.1 fixing overlapping high point series highlight and improved LineChart perf (up to 33%) #451: The changes in the main PR regarding the PercentileLineChart.svelte component's logic and structure are directly related to the modifications made to the onbrushend event handler in the retrieved PR.
• Migrate ECharts usage to LayerChart #251: The changes in the main PR for PercentileLineChart.svelte involve modifications to the LineChart component's structure and logic, while the retrieved PR introduces a new component FeaturesLineChart that also utilizes the LineChart component.

Suggested reviewers

• ken-zlai

Poem

A refactor blooms in code today,
With constants where inline once lay,
Type hints clear the data's way,
Performance sings, no delay! 🎉
CodeRabbit cheers, hip-hip-hooray!

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between 3030ba0 and 7995fa8.

📒 Files selected for processing (1)

• frontend/src/lib/components/charts/PercentileLineChart.svelte (3 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• frontend/src/lib/components/charts/PercentileLineChart.svelte

⏰ Context from checks skipped due to timeout of 90000ms (2)

• GitHub Check: frontend_tests
• GitHub Check: enforce_triggered_workflows

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[ken-zlai]

this is insane - amazing! loading the summary page is super snappy now. great job!