No deep equal check in memo rule

[kacper-mikolajczak]

$ Expensify/App#76362

Intro

Create a new ESLint rule no-deep-equal-in-memo that enforces the PERF-5 guideline by detecting deep equality checks in React.memo comparison functions and suggesting shallow comparisons instead.

Key Design Decisions

1. No Autofix: Cannot automatically determine which properties should be compared, so manual intervention is required
2. Detect Both Import Styles: Handle both React.memo and memo named imports
3. Deep Comparison Functions: Focus on deepEqual, isEqual, and _.isEqual as the most common patterns
4. Clear Error Messages: Include the specific function name in the error message to help developers understand what needs to be changed
5. AST Traversal: Similar to prefer-narrow-hook-dependencies, use recursive AST traversal to find deep comparison calls within the comparison function body

Rule Logic

• Detect React.memo() calls (namespace import) and memo() calls (named import from 'react')
• Check if a second argument (comparison function) is provided
• Traverse the comparison function body to find calls to deep comparison functions:
  • deepEqual(...) - direct calls
  • isEqual(...) - direct calls or lodash
  • _.isEqual(...) - lodash with underscore
• Report violations when deep comparison functions are found

[github-actions]

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[mountiny]

Looks good to me, how much time does it add to the total eslint time?

[kacper-mikolajczak]

@mountiny Last CI run was about 25 minutes, so it seems there's no much added overhead. However, job was failing - I will report back to you with complete green check run when we deal with all the remaining errors.