Enhancement (QoL): attempt to localize firstDayOfWeek for date picker (#13999)

src-ui/src/app/utils/ngb-input-date-picker-config.spec.ts

@@ -0,0 +1,84 @@
+import { LOCALE_ID } from '@angular/core'
+import { TestBed } from '@angular/core/testing'
+import { NgbInputDatepickerConfig } from '@ng-bootstrap/ng-bootstrap'
+import { PngxDatePickerConfig } from './ngb-input-date-picker-config'
+
+describe('PngxDatePickerConfig', () => {
+  const configureLocale = (locale: string) => {
+    TestBed.configureTestingModule({
+      providers: [
+        { provide: LOCALE_ID, useValue: locale },
+        {
+          provide: NgbInputDatepickerConfig,
+          useClass: PngxDatePickerConfig,
+        },
+      ],
+    })
+  }
+
+  it('uses Sunday as the first day of the week for en-US', () => {
+    configureLocale('en-US')
+
+    const config = TestBed.inject(NgbInputDatepickerConfig)
+
+    expect(config).toBeInstanceOf(PngxDatePickerConfig)
+    expect(config.firstDayOfWeek).toEqual(7)
+  })
+
+  it('uses Monday as the first day of the week for de-DE', () => {
+    configureLocale('de-DE')
+
+    const config = TestBed.inject(NgbInputDatepickerConfig)
+
+    expect(config.firstDayOfWeek).toEqual(1)
+  })
+
+  it('supports browsers that provide getWeekInfo() and weekInfo', () => {
+    const getWeekInfo = jest.fn().mockReturnValue({ firstDay: 6 })
+    const originalDescriptor = Object.getOwnPropertyDescriptor(
+      Intl.Locale.prototype,
+      'getWeekInfo'
+    )
+    Object.defineProperty(Intl.Locale.prototype, 'getWeekInfo', {
+      configurable: true,
+      value: getWeekInfo,
+    })
+    let config: NgbInputDatepickerConfig
+    try {
+      configureLocale('ar-EG')
+      config = TestBed.inject(NgbInputDatepickerConfig)
+    } finally {
+      if (originalDescriptor) {
+        Object.defineProperty(
+          Intl.Locale.prototype,
+          'getWeekInfo',
+          originalDescriptor
+        )
+      } else {
+        delete Intl.Locale.prototype['getWeekInfo']
+      }
+    }
+
+    expect(getWeekInfo).toHaveBeenCalledTimes(1)
+    expect(config.firstDayOfWeek).toEqual(6)
+
+    Object.defineProperty(Intl.Locale.prototype, 'weekInfo', {
+      configurable: true,
+      value: { firstDay: 5 },
+    })
+    Object.defineProperty(Intl.Locale.prototype, 'getWeekInfo', {
+      configurable: true,
+      value: undefined,
+    })
+    try {
+      TestBed.resetTestingModule()
+      configureLocale('ar-EG')
+      config = TestBed.inject(NgbInputDatepickerConfig)
+    } finally {
+      delete Intl.Locale.prototype['weekInfo']
+      delete Intl.Locale.prototype['getWeekInfo']
+    }
+
+    expect(config.firstDayOfWeek).toEqual(5)
+  })
+})

src-ui/src/app/utils/ngb-input-date-picker-config.ts

@@ -0,0 +1,20 @@
+import { inject, Injectable, LOCALE_ID } from '@angular/core'
+import { NgbInputDatepickerConfig } from '@ng-bootstrap/ng-bootstrap'
+
+@Injectable()
+export class PngxDatePickerConfig extends NgbInputDatepickerConfig {
+  currentLocale = inject(LOCALE_ID)
+
+  constructor() {
+    super()
+    const localeInfo = new Intl.Locale(this.currentLocale) as any
+    let firstDay
+    if (localeInfo?.getWeekInfo) firstDay = localeInfo.getWeekInfo?.().firstDay
+    else if (localeInfo?.weekInfo?.firstDay)
+      firstDay = localeInfo.weekInfo.firstDay
+
+    if (firstDay !== undefined) {
+      this.firstDayOfWeek = firstDay
+    }
+  }
+}