SimpleFinanceDash/.planning/phases/04-chart-polish-and-bug-fixes/04-02-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
04-chart-polish-and-bug-fixes	02	ui	recharts react typescript i18n locale formatCurrency	phase provides 04-chart-polish-and-bug-fixes formatCurrency(amount, currency?, locale?) with defensive locale guard	Custom Recharts Tooltip on ExpenseBreakdown pie chart showing category name + formatted currency Custom Recharts Tooltip on AvailableBalance donut chart showing segment name + formatted currency AvailableBalance center text locale-aware via locale prop DashboardPage threads user.preferred_locale from useAuth to both chart components	future-chart-components locale-threading	added patterns Custom Recharts Tooltip via content prop with shadcn design-token styling (bg-background, border-border/50, shadow-xl) Locale threaded from useAuth() in page component down to leaf chart components as optional prop with 'en' default	created modified frontend/src/components/ExpenseBreakdown.tsx frontend/src/components/AvailableBalance.tsx frontend/src/pages/DashboardPage.tsx frontend/src/pages/DashboardPage.test.tsx	Custom Tooltip content renderer replicates ChartTooltipContent styling without importing shadcn source — aligned with project rule forbidding edits to src/components/ui/ useAuth() called in DashboardPage is idempotent — reads from same React state as App.tsx, no double-fetch Locale threading scoped to chart components only in this plan — table components (BillsTracker, etc.) use 'en' default from formatCurrency, full threading deferred DashboardPage.test.tsx mocks useAuth to prevent i18n initReactI18next import error triggered by new useAuth dependency	Pattern: locale prop on chart components is optional with 'en' default — callers that don't have locale context still work	IXTN-04	10min	2026-03-12

Phase 4 Plan 02: Chart Tooltip Currency Formatting Summary

Custom Recharts tooltips on both charts show locale-aware formatted currency, with user.preferred_locale threaded from useAuth through DashboardPage

Performance

• Duration: 10 min
• Started: 2026-03-12T09:25:00Z
• Completed: 2026-03-12T09:35:00Z
• Tasks: 2
• Files modified: 4

Accomplishments

• ExpenseBreakdown pie chart replaces bare <Tooltip /> with custom content renderer showing category name and formatCurrency-formatted value
• AvailableBalance donut chart gains a Tooltip for the first time, using same custom renderer pattern; center text also receives locale
• DashboardPage imports useAuth, derives userLocale with fallback to 'en', and passes it as locale prop to both chart components

Task Commits

Each task was committed atomically:

1. Task 1: Add locale prop and custom Tooltip to both chart components - f141c4f (feat)
2. Task 2: Thread user locale from useAuth through DashboardPage to chart components - 5a70899 (feat)

Plan metadata: (docs commit — see final_commit)

Files Created/Modified

• frontend/src/components/ExpenseBreakdown.tsx - Added locale prop, formatCurrency import, custom Tooltip content renderer
• frontend/src/components/AvailableBalance.tsx - Added locale prop, Tooltip import, custom Tooltip content renderer, locale passed to center text formatCurrency
• frontend/src/pages/DashboardPage.tsx - Added useAuth import, userLocale derivation, locale prop passed to AvailableBalance and ExpenseBreakdown
• frontend/src/pages/DashboardPage.test.tsx - Added useAuth mock to prevent i18n initReactI18next error

Decisions Made

• Custom Tooltip uses shadcn CSS variable classes (bg-background, border-border/50, shadow-xl) rather than importing ChartTooltipContent — aligns with project rule against editing ui/ source files
• Locale threading scoped to chart components only — table components already have 'en' default via formatCurrency, full threading deferred per plan spec
• DashboardPage.test.tsx required a useAuth mock because useAuth imports @/i18n which calls i18n.use(initReactI18next) — the existing react-i18next mock did not export initReactI18next

Deviations from Plan

Auto-fixed Issues

1. [Rule 1 - Bug] DashboardPage test broken by new useAuth import

• Found during: Task 2 (Thread user locale from useAuth through DashboardPage)
• Issue: Adding useAuth to DashboardPage caused the test file to fail with "No initReactI18next export defined on react-i18next mock" — because useAuth transitively imports @/i18n which calls i18n.use(initReactI18next)
• Fix: Added vi.mock('@/hooks/useAuth', ...) to DashboardPage.test.tsx, returning a user with preferred_locale: 'en'
• Files modified: frontend/src/pages/DashboardPage.test.tsx
• Verification: Full test suite passes (51 tests), production build succeeds with no TypeScript errors
• Committed in: 5a70899 (Task 2 commit)

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Total deviations: 1 auto-fixed (Rule 1 - bug introduced by task change) Impact on plan: Auto-fix was necessary to restore test suite. No scope creep.

Issues Encountered

None beyond the auto-fixed test breakage above.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• Both chart components now display locale-aware currency tooltips
• Locale threading pattern established: page-level useAuth() call + optional locale prop with 'en' default
• Ready to extend locale threading to table components if desired in a future plan

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Phase: 04-chart-polish-and-bug-fixes Completed: 2026-03-12