Imported from Shobhit-A/report-app (.claude/skills/project-auditor/SKILL.md). Install upstream with npx skills add Shobhit-A/report-app --skill project-auditor. Copyright stays with the author.

Report App — Detailed Audit Checklist

User Flows

• Can a user select a date range and see updated data immediately?
• Are filters applied correctly and reflected in all charts/tables on the page?
• Can a user drill down into a data point for more detail?
• Can a user export the report (PDF, CSV, Excel)?
• Are reports shareable (link, email)?
• Does the page remember filters on refresh (URL params or localStorage)?

Data Correctness

• Totals in summary cards match the sum in detail tables
• Chart data matches table data (same filters applied)
• Percentages add up to 100% where expected
• "No data" periods shown as 0, not gaps in charts
• Date ranges are inclusive of start and end day

Performance

• Large datasets paginated (not loading 10,000 rows at once)
• Charts use aggregated data from server, not raw rows
• Filters trigger a new API call, not client-side filtering of a giant array
• Debounce on search/filter inputs (don't hit API on every keystroke)
• Memoized expensive chart computations

UI Components

• All charts have: title, axis labels, legend, tooltips on hover
• Date range picker shows clear start/end labels
• Filter panel is collapsible on mobile
• Table columns are sortable with visual sort indicator
• Table is paginated with page size selector
• Numbers formatted with locale (commas, currency symbols)
• Percentages shown with % sign
• Loading skeleton shown while data fetches
• Empty state with helpful message when no data matches filters
• Error state with retry button if API fails

API Design

• Report endpoint accepts: startDate, endDate, filters[], groupBy, page, pageSize
• Response includes: data[], total, page, pageSize, summary{}
• Slow queries cached (Redis or in-memory) for common date ranges
• Query uses indexed columns for date range filtering

Export Feature

• Export applies same filters as current view
• CSV includes all columns (not just visible ones)
• PDF export matches the on-screen layout
• Export filename includes date range: report_2024-01-01_2024-01-31.csv

Common Bugs in Report Apps

• Filter change updates one chart but not another (filter state not shared)
• "Last 30 days" off-by-one (today not included or double-included)
• Chart tooltip shows raw data key instead of human-readable label
• Table sort resets to page 1 but doesn't refetch — shows wrong page data
• Export button exports previous filter state (async state update race condition)
• Large number rendering: 1000000 shown instead of 1,000,000
• Negative values in charts displayed as 0 (clamped incorrectly)
• Timezone: report shows UTC dates but user expects local timezone