perf(ui): optimize table rendering by memoizing styled characters

[devr0306]

Summary

Precomputed styled headers and rows instead of computing them multiple times.
Also fixed an edge case where lesser headers than rows would cause a runtime crash.

Details

Made toStyledChars get called only once in the beginning instead of multiple times and memoized the values for styled rows and headers.
Stopped using headers.length to get column count and using the max of headers and rows.

Related Issues

Fixes #18763

How to Validate

Run the tests in TableRenderer.test.tsx: npm test -w @google/gemini-cli -- src/ui/utils/TableRenderer.test.tsx . They should all pass.

Manual testing:
Ask Gemini to generate a table with long columns

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-code-assist]

Summary of Changes

Hello @devr0306, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the performance of the TableRenderer component by implementing memoization for styled headers and rows. By precomputing these values, it eliminates redundant and computationally intensive calls to toStyledCharacters, leading to a more efficient and faster rendering process for tables. This change directly addresses and fixes issue #18763.

Highlights

• Performance Optimization: Optimized table rendering by precomputing styled headers and rows, reducing redundant calls to toStyledCharacters.
• Memoization: Implemented useMemo for styledHeaders and styledRows to cache their values and prevent re-computation.
• Refactored calculateWidths: Modified the calculateWidths function to directly accept StyledChar[] instead of a raw string, leveraging the precomputed styled characters.

Changelog

• packages/cli/src/ui/utils/TableRenderer.tsx
  • Modified the calculateWidths function signature to accept StyledChar[] directly, removing an internal call to toStyledCharacters.
  • Introduced styledHeaders and styledRows using useMemo to pre-process all header and cell content into StyledChar[] arrays.
  • Updated the logic within the main useMemo hook to utilize these precomputed styledHeaders and styledRows for constraint calculation and wrapping.
  • Adjusted the dependency array of the main useMemo hook to reflect the new styledHeaders and styledRows dependencies.

Activity

• The pull request was created by devr0306.
• It addresses and fixes issue Optimize table rendering #18763.
• No further human activity (comments, reviews) has been recorded yet.

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[gemini-code-assist]

Code Review

This pull request effectively optimizes the table rendering by pre-computing and memoizing styled characters for headers and rows, which prevents expensive re-calculations. I've identified one critical edge case where providing empty headers could lead to a runtime crash, and I've provided a suggestion to fix it. Additionally, I've noted an area for improvement in space distribution logic based on repository guidelines.

[github-actions]

Size Change: +512 B (0%)

Total Size: 24.3 MB

ℹ️ View Unchanged

Filename	Size	Change
./bundle/gemini.js	24.3 MB	+512 B (0%)
./bundle/sandbox-macos-permissive-closed.sb	1.03 kB	0 B
./bundle/sandbox-macos-permissive-open.sb	890 B	0 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB	0 B
./bundle/sandbox-macos-restrictive-closed.sb	3.29 kB	0 B
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB	0 B
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB	0 B

_{compressed-size-action}

[jacob314]