fix(material/datepicker): add i18n strings

src/material/datepicker/datepicker-intl.ts

@@ -19,40 +19,51 @@ export class MatDatepickerIntl {
   readonly changes: Subject<void> = new Subject<void>();
 
   /** A label for the calendar popup (used by screen readers). */
-  calendarLabel: string = 'Calendar';
+  calendarLabel = 'Calendar';
 
   /** A label for the button used to open the calendar popup (used by screen readers). */
-  openCalendarLabel: string = 'Open calendar';
+  openCalendarLabel = 'Open calendar';
 
   /** Label for the button used to close the calendar popup. */
-  closeCalendarLabel: string = 'Close calendar';
+  closeCalendarLabel = 'Close calendar';
 
   /** A label for the previous month button (used by screen readers). */
-  prevMonthLabel: string = 'Previous month';
+  prevMonthLabel = 'Previous month';
 
   /** A label for the next month button (used by screen readers). */
-  nextMonthLabel: string = 'Next month';
+  nextMonthLabel = 'Next month';
 
   /** A label for the previous year button (used by screen readers). */
-  prevYearLabel: string = 'Previous year';
+  prevYearLabel = 'Previous year';
 
   /** A label for the next year button (used by screen readers). */
-  nextYearLabel: string = 'Next year';
+  nextYearLabel = 'Next year';
 
   /** A label for the previous multi-year button (used by screen readers). */
-  prevMultiYearLabel: string = 'Previous 24 years';
+  prevMultiYearLabel = 'Previous 24 years';
 
   /** A label for the next multi-year button (used by screen readers). */
-  nextMultiYearLabel: string = 'Next 24 years';
+  nextMultiYearLabel = 'Next 24 years';
 
   /** A label for the 'switch to month view' button (used by screen readers). */
-  switchToMonthViewLabel: string = 'Choose date';
+  switchToMonthViewLabel = 'Choose date';
 
   /** A label for the 'switch to year view' button (used by screen readers). */
-  switchToMultiYearViewLabel: string = 'Choose month and year';
+  switchToMultiYearViewLabel = 'Choose month and year';
 
-  /** Formats a range of years. */
+  /** A label for the first date of a range of dates (used by screen readers). */
+  startDateLabel = 'Start date';
+
+  /** A label for the last date of a range of dates (used by screen readers). */
+  endDateLabel = 'End date';
+
+  /** Formats a range of years (used for visuals). */
   formatYearRange(start: string, end: string): string {
     return `${start} \u2013 ${end}`;
   }
+
+  /** Formats a label for a range of years (used by screen readers). */
+  formatYearRangeLabel(start: string, end: string): string {
+    return `${start} to ${end}`;
+  }
 }

tools/public_api_guard/material/datepicker.md

@@ -525,14 +525,17 @@ export class MatDatepickerIntl {
     calendarLabel: string;
     readonly changes: Subject<void>;
     closeCalendarLabel: string;
+    endDateLabel: string;
     formatYearRange(start: string, end: string): string;
+    formatYearRangeLabel(start: string, end: string): string;
     nextMonthLabel: string;
     nextMultiYearLabel: string;
     nextYearLabel: string;
     openCalendarLabel: string;
     prevMonthLabel: string;
     prevMultiYearLabel: string;
     prevYearLabel: string;
+    startDateLabel: string;
     switchToMonthViewLabel: string;
     switchToMultiYearViewLabel: string;
     // (undocumented)