perf(web): reuse locale formatters

vehicle-data-platform/apps/web/src/v2/domain/access.ts

@@ -1,5 +1,9 @@
 import type { AccessProtocolThreshold, AccessThresholdConfig, AccessVehicleRow } from '../../api/types';
 
+const accessTimeFormatter = new Intl.DateTimeFormat('zh-CN', {
+  year: 'numeric', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false
+});
+
 export const accessStateLabels: Record<AccessVehicleRow['onlineState'], string> = {
   online: '在线',
   offline: '离线',
@@ -22,9 +26,7 @@ export function formatAccessTime(value: string) {
   if (!value) return '—';
   const parsed = new Date(value);
   if (Number.isNaN(parsed.getTime())) return '—';
-  return new Intl.DateTimeFormat('zh-CN', {
-    year: 'numeric', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false
-  }).format(parsed).replace(/\//g, '-');
+  return accessTimeFormatter.format(parsed).replace(/\//g, '-');
 }
 
 export function thresholdForProtocol(config: AccessThresholdConfig, protocol: string) {

vehicle-data-platform/apps/web/src/v2/domain/alert.ts

@@ -1,4 +1,7 @@
 import type { AlertEvent, AlertRule, AlertSeverity, AlertStatus } from '../../api/types';
+import { formatZhNumber } from './formatters';
+
+const alertTimeFormatter = new Intl.DateTimeFormat('zh-CN', { month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false });
 
 export const severityLabels: Record<AlertSeverity, string> = { critical: '紧急', major: '重要', minor: '一般' };
 export const statusLabels: Record<AlertStatus, string> = { unprocessed: '未处理', processing: '处理中', recovered: '已恢复', closed: '已关闭', ignored: '已忽略' };
@@ -10,18 +13,18 @@ export function formatAlertTime(value: string) {
   if (!value) return '—';
   const date = new Date(value);
   if (Number.isNaN(date.getTime())) return value.replace('T', ' ').slice(0, 19);
-  return new Intl.DateTimeFormat('zh-CN', { month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false }).format(date).replace(/\//g, '-');
+  return alertTimeFormatter.format(date).replace(/\//g, '-');
 }
 
 export function alertValue(event: Pick<AlertEvent, 'triggerValue' | 'unit'>) {
-  return `${Number(event.triggerValue.toFixed(2)).toLocaleString('zh-CN')} ${event.unit}`.trim();
+  return `${formatZhNumber(Number(event.triggerValue.toFixed(2)), 2)} ${event.unit}`.trim();
 }
 
 export function thresholdText(event: Pick<AlertEvent, 'operator' | 'threshold' | 'thresholdHigh' | 'unit' | 'durationSec'>) {
   const duration = event.durationSec > 0 ? `，持续 ${event.durationSec} 秒` : '';
   if (event.operator === 'between' || event.operator === 'outside') return `${operatorLabels[event.operator]} ${event.threshold}–${event.thresholdHigh} ${event.unit}${duration}`.trim();
   if (event.operator === 'changed') return `状态发生变化${duration}`;
-  return `${operatorLabels[event.operator] ?? event.operator} ${Number(event.threshold.toFixed(2)).toLocaleString('zh-CN')} ${event.unit}${duration}`.trim();
+  return `${operatorLabels[event.operator] ?? event.operator} ${formatZhNumber(Number(event.threshold.toFixed(2)), 2)} ${event.unit}${duration}`.trim();
 }
 
 export function ruleCondition(rule: AlertRule, labels: Record<string, string> = metricLabels) {

vehicle-data-platform/apps/web/src/v2/domain/formatters.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from 'vitest';
+import { formatZhNumber } from './formatters';
+
+describe('formatZhNumber', () => {
+  it('formats Chinese locale numbers with independent precision caches', () => {
+    expect(formatZhNumber(1234.56)).toBe('1,235');
+    expect(formatZhNumber(1234.56, 1)).toBe('1,234.6');
+    expect(formatZhNumber(1234.56, 2)).toBe('1,234.56');
+    expect(formatZhNumber(1234.56, 1)).toBe('1,234.6');
+  });
+
+  it('preserves Intl handling for non-finite numeric values', () => {
+    expect(formatZhNumber(Number.NaN, 2)).toBe('NaN');
+  });
+});

vehicle-data-platform/apps/web/src/v2/domain/formatters.ts

@@ -0,0 +1,10 @@
+const zhNumberFormatters = new Map<number, Intl.NumberFormat>();
+
+export function formatZhNumber(value: number, maximumFractionDigits = 0) {
+  let formatter = zhNumberFormatters.get(maximumFractionDigits);
+  if (!formatter) {
+    formatter = new Intl.NumberFormat('zh-CN', { maximumFractionDigits });
+    zhNumberFormatters.set(maximumFractionDigits, formatter);
+  }
+  return formatter.format(value);
+}

vehicle-data-platform/apps/web/src/v2/domain/history.ts

@@ -1,4 +1,5 @@
 import type { HistoryDataRow, HistoryExportJob, HistoryMetricDefinition, HistorySeries, HistorySeriesResponse } from '../../api/types';
+import { formatZhNumber } from './formatters';
 
 export const HISTORY_EXPORT_POLL_MS = {
   running: 3_000,
@@ -23,7 +24,7 @@ export function parseHistoryKeywords(value: string) {
 
 export function formatHistoryValue(value: unknown, metric?: HistoryMetricDefinition) {
   if (value == null || value === '') return '—';
-  const formatted = typeof value === 'number' ? new Intl.NumberFormat('zh-CN', { maximumFractionDigits: 6 }).format(value) : String(value);
+  const formatted = typeof value === 'number' ? formatZhNumber(value, 6) : String(value);
   return metric?.unit ? `${formatted} ${metric.unit}` : formatted;
 }
 

vehicle-data-platform/apps/web/src/v2/domain/monitor.ts

@@ -1,4 +1,5 @@
 import type { VehicleRealtimeRow } from '../../api/types';
+import { formatZhNumber } from './formatters';
 
 export type FleetStatus = 'online' | 'offline' | 'driving' | 'idle' | 'alert' | 'unknown';
 
@@ -31,5 +32,5 @@ export function relativeFreshness(value: string) {
 }
 
 export function formatNumber(value: number, maximumFractionDigits = 0) {
-  return new Intl.NumberFormat('zh-CN', { maximumFractionDigits }).format(value);
+  return formatZhNumber(value, maximumFractionDigits);
 }

vehicle-data-platform/apps/web/src/v2/domain/telemetry.ts

@@ -1,6 +1,8 @@
+import { formatZhNumber } from './formatters';
+
 export function formatTelemetryValue(value: unknown) {
   if (typeof value === 'number' && Number.isFinite(value)) {
-    return new Intl.NumberFormat('zh-CN', { maximumFractionDigits: 2 }).format(value);
+    return formatZhNumber(value, 2);
   }
   if (typeof value === 'boolean') return value ? '是' : '否';
   if (typeof value === 'string') return value || '—';