fix: format week number with numerals

src/DayPicker.tsx

@@ -531,7 +531,7 @@ export function DayPicker(initialProps: DayPickerProps) {
                               scope="row"
                               role="rowheader"
                             >
-                              {formatWeekNumber(week.weekNumber)}
+                              {formatWeekNumber(week.weekNumber, dateLib)}
                             </components.WeekNumber>
                           )}
                           {week.days.map((day: CalendarDay) => {

src/classes/DateLib.ts

@@ -162,7 +162,7 @@ export class DateLib {
    * @param value The number to format.
    * @returns The formatted number.
    */
-  formatNumber(value: number): string {
+  formatNumber(value: number | string): string {
     return this.replaceDigits(value.toString());
   }
 

src/formatters/formatWeekNumber.test.ts

@@ -1,5 +1,16 @@
+import { DateLib } from "../classes";
+
 import { formatWeekNumber } from "./formatWeekNumber";
 
 test("should return the formatted week number", () => {
   expect(formatWeekNumber(10)).toEqual("10");
 });
+
+test("should return the formatted week number with leading zero", () => {
+  expect(formatWeekNumber(1)).toEqual("01");
+});
+
+test("should format with the provided numeral system", () => {
+  const dateLib = new DateLib({ numerals: "arab" });
+  expect(formatWeekNumber(1, dateLib)).toEqual("٠١");
+});

src/formatters/formatWeekNumber.ts

@@ -1,13 +1,15 @@
+import { defaultDateLib } from "../classes/DateLib.js";
+
 /**
  * Format the week number.
  *
  * @defaultValue `weekNumber.toLocaleString()` with a leading zero for single-digit numbers
  * @group Formatters
  * @see https://daypicker.dev/docs/translation#custom-formatters
  */
-export function formatWeekNumber(weekNumber: number) {
+export function formatWeekNumber(weekNumber: number, dateLib = defaultDateLib) {
   if (weekNumber < 10) {
-    return `0${weekNumber.toLocaleString()}`;
+    return dateLib.formatNumber(`0${weekNumber.toLocaleString()}`);
   }
-  return `${weekNumber.toLocaleString()}`;
+  return dateLib.formatNumber(`${weekNumber.toLocaleString()}`);
 }