- init

src/store/format.ts

@@ -0,0 +1,107 @@
+import { isError, type CellValue } from '../engine';
+import type { CellNumFmt } from './types';
+
+/**
+ * Locale used to render numeric values. `'plain'` is not a real locale -- it
+ * renders the bare JS number (`.` decimal, no grouping).
+ *
+ * A *display* setting only. `rawString()` (CSV / XLSX export) stays
+ * locale-neutral so round-trips are lossless.
+ */
+export type NumberLocale =
+  | 'plain'
+  | 'de-DE'
+  | 'de-CH'
+  | 'en-US'
+  | 'en-GB'
+  | 'fr-FR'
+  | 'it-IT';
+
+export const NUMBER_LOCALES: ReadonlyArray<{ id: NumberLocale; label: string }> = [
+  { id: 'plain', label: 'Ohne Trennzeichen · 1234.5' },
+  { id: 'de-DE', label: 'Deutsch (DE) · 1.234,5' },
+  { id: 'de-CH', label: 'Schweiz (CH) · 1’234.5' },
+  { id: 'en-US', label: 'English (US) · 1,234.5' },
+  { id: 'en-GB', label: 'English (UK) · 1,234.5' },
+  { id: 'fr-FR', label: 'Français (FR) · 1 234,5' },
+  { id: 'it-IT', label: 'Italiano (IT) · 1.234,5' },
+];
+
+const LOCALE_IDS = new Set(NUMBER_LOCALES.map((l) => l.id));
+export function isNumberLocale(x: unknown): x is NumberLocale {
+  return typeof x === 'string' && LOCALE_IDS.has(x as NumberLocale);
+}
+export const DEFAULT_LOCALE: NumberLocale = 'de-DE';
+
+/** Cell number-format options offered in the UI. */
+export const NUM_FORMATS: ReadonlyArray<{ id: CellNumFmt; label: string }> = [
+  { id: 'auto', label: 'Automatisch' },
+  { id: 'plain', label: 'Ohne Formatierung' },
+  { id: 'int', label: 'Ganzzahl · 1.235' },
+  { id: 'dec1', label: '1 Nachkommastelle · 1.234,6' },
+  { id: 'dec2', label: '2 Nachkommastellen · 1.234,56' },
+  { id: 'pct0', label: 'Prozent · 12 %' },
+  { id: 'pct2', label: 'Prozent · 12,34 %' },
+];
+const NUM_FMT_IDS = new Set(NUM_FORMATS.map((f) => f.id));
+export function isCellNumFmt(x: unknown): x is CellNumFmt {
+  return typeof x === 'string' && NUM_FMT_IDS.has(x as CellNumFmt);
+}
+
+const round10 = (n: number) => Math.round(n * 1e10) / 1e10;
+
+function nf(locale: NumberLocale, opts: Intl.NumberFormatOptions): Intl.NumberFormat {
+  // for the pseudo-locale 'plain' use en-US digits but turn grouping off
+  return new Intl.NumberFormat(locale === 'plain' ? 'en-US' : locale, {
+    useGrouping: locale !== 'plain',
+    ...opts,
+  });
+}
+
+/** Render a computed value for display (grid cell / status bar / chart). */
+export function formatValue(
+  v: CellValue,
+  locale: NumberLocale = DEFAULT_LOCALE,
+  numFmt: CellNumFmt = 'auto',
+): string {
+  if (v === null) return '';
+  if (isError(v)) return v.code;
+  if (typeof v !== 'number') return v;
+  if (!Number.isFinite(v)) return '#NUM!';
+
+  const n = round10(v);
+  switch (numFmt) {
+    case 'plain':
+      return String(n);
+    case 'int':
+      return nf(locale, { maximumFractionDigits: 0 }).format(n);
+    case 'dec1':
+      return nf(locale, { minimumFractionDigits: 1, maximumFractionDigits: 1 }).format(n);
+    case 'dec2':
+      return nf(locale, { minimumFractionDigits: 2, maximumFractionDigits: 2 }).format(n);
+    case 'pct0':
+      return nf(locale, { style: 'percent', maximumFractionDigits: 0 }).format(n);
+    case 'pct2':
+      return nf(locale, {
+        style: 'percent',
+        minimumFractionDigits: 2,
+        maximumFractionDigits: 2,
+      }).format(n);
+    default: // 'auto'
+      return locale === 'plain'
+        ? String(n)
+        : nf(locale, { maximumFractionDigits: 10 }).format(n);
+  }
+}
+
+/** Plain (ungrouped, `.`-decimal) string -- machine-readable, for CSV / XLSX. */
+export function rawString(v: CellValue): string {
+  if (v === null) return '';
+  if (isError(v)) return v.code;
+  if (typeof v === 'number') return String(round10(v));
+  return v;
+}
+
+export function isNumeric(v: CellValue): boolean {
+  return typeof v === 'number' && Number.isFinite(v);
+}