8.8 KiB
8.8 KiB
phase, plan, type, wave, depends_on, files_modified, autonomous, requirements, must_haves
| phase | plan | type | wave | depends_on | files_modified | autonomous | requirements | must_haves | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| 07-weight-unit-selection | 01 | tdd | 1 |
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true |
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Purpose: Establish the conversion contracts (type, function, hook) that Plan 02 will wire into every component. TDD approach ensures the conversion math is correct before any UI work.
Output: Working formatWeight(grams, unit) with tests green, useWeightUnit() hook ready for consumption.
<execution_context> @/home/jlmak/.claude/get-shit-done/workflows/execute-plan.md @/home/jlmak/.claude/get-shit-done/templates/summary.md </execution_context>
@.planning/PROJECT.md @.planning/ROADMAP.md @.planning/STATE.md @.planning/phases/07-weight-unit-selection/07-RESEARCH.md@src/client/lib/formatters.ts @src/client/hooks/useSettings.ts
From src/client/lib/formatters.ts (current):
export function formatWeight(grams: number | null | undefined): string {
if (grams == null) return "--";
return `${Math.round(grams)}g`;
}
export function formatPrice(cents: number | null | undefined): string {
if (cents == null) return "--";
return `$${(cents / 100).toFixed(2)}`;
}
From src/client/hooks/useSettings.ts:
export function useSetting(key: string) {
return useQuery({
queryKey: ["settings", key],
queryFn: async () => {
try {
const result = await apiGet<Setting>(`/api/settings/${key}`);
return result.value;
} catch (err: any) {
if (err?.status === 404) return null;
throw err;
}
},
});
}
export function useUpdateSetting() {
const queryClient = useQueryClient();
return useMutation({
mutationFn: ({ key, value }: { key: string; value: string }) =>
apiPut<Setting>(`/api/settings/${key}`, { value }),
onSuccess: (_data, variables) => {
queryClient.invalidateQueries({ queryKey: ["settings", variables.key] });
},
});
}
- formatWeight(100, "g") -> "100g"
- formatWeight(100, "oz") -> "3.5 oz"
- formatWeight(1000, "lb") -> "2.20 lb"
- formatWeight(1500, "kg") -> "1.50 kg"
- formatWeight(null, "oz") -> "--"
- formatWeight(undefined, "kg") -> "--"
- formatWeight(100) -> "100g" (default unit, backward compatible)
- formatWeight(0, "oz") -> "0.0 oz"
- formatWeight(5, "lb") -> "0.01 lb" (small weight precision)
- formatWeight(50000, "kg") -> "50.00 kg" (large weight)
Run tests — they should fail because formatWeight does not accept a unit parameter yet.
GREEN: Modify `src/client/lib/formatters.ts`:
- Export `type WeightUnit = "g" | "oz" | "lb" | "kg"`
- Add constants: `GRAMS_PER_OZ = 28.3495`, `GRAMS_PER_LB = 453.592`, `GRAMS_PER_KG = 1000`
- Change signature to `formatWeight(grams: number | null | undefined, unit: WeightUnit = "g")`
- Add switch statement after the null guard for unit-specific conversion and formatting
- Leave `formatPrice` completely untouched
Run tests — all should pass.
REFACTOR: None expected — the code is already minimal.
```typescript
import { useSetting } from "./useSettings";
import type { WeightUnit } from "../lib/formatters";
const VALID_UNITS: WeightUnit[] = ["g", "oz", "lb", "kg"];
export function useWeightUnit(): WeightUnit {
const { data } = useSetting("weightUnit");
if (data && VALID_UNITS.includes(data as WeightUnit)) {
return data as WeightUnit;
}
return "g";
}
```
This hook:
- Wraps `useSetting("weightUnit")` for a typed return value
- Validates the stored value is a known unit (protects against bad data)
- Defaults to "g" when no setting exists (backward compatible — UNIT-03 persistence works via existing settings API)
- Returns `WeightUnit` type so components can pass directly to `formatWeight`
<success_criteria>
- formatWeight("g") produces identical output to the old function (backward compatible)
- formatWeight with oz/lb/kg produces correct conversions with appropriate decimal precision
- WeightUnit type is exported for use by Plan 02 components
- useWeightUnit hook is ready for components to consume
- All existing tests remain green (no regressions) </success_criteria>