feat: ethiopic calendar

.github/CODEOWNERS

@@ -0,0 +1 @@
+*       @gpbl

ethiopic.d.ts

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+export * from "./dist/cjs/ethiopic/index.d.ts";

ethiopic.js

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+/* eslint-disable @typescript-eslint/no-require-imports */
+/* eslint-disable no-undef */
+const ethiopic = require("./dist/cjs/ethiopic/index.js");
+module.exports = ethiopic;

examples/Ethiopic.test.tsx

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+import React from "react";
+
+import { grid } from "@/test/elements";
+import { render } from "@/test/render";
+
+import { Ethiopic } from "./Ethiopic.jsx";
+
+const today = new Date(2024, 11, 22);
+
+beforeAll(() => jest.setSystemTime(today));
+afterAll(() => jest.useRealTimers());
+
+test("should render ታህሳስ ፳፻፲፯", () => {
+  render(<Ethiopic />);
+  expect(grid("ታህሳስ ፳፻፲፯")).toBeInTheDocument();
+});

examples/Ethiopic.tsx

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+import React from "react";
+
+import { DayPicker } from "react-day-picker/ethiopic";
+
+export function Ethiopic() {
+  return <DayPicker />;
+}

examples/EthiopicGeez.test.tsx

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+import React from "react";
+
+import { grid } from "@/test/elements";
+import { render } from "@/test/render";
+
+import { EthiopicGeez } from "./EthiopicGeez";
+
+const today = new Date(2024, 11, 22);
+
+beforeAll(() => jest.setSystemTime(today));
+afterAll(() => jest.useRealTimers());
+
+test("should render Tahsas 2017 with latin numerals", () => {
+  render(<EthiopicGeez />);
+  expect(grid("Tahsas 2017")).toBeInTheDocument();
+});
+
+test("should render December 2024 with latin numerals", () => {
+  render(<EthiopicGeez />);
+  expect(grid("December 2024")).toBeInTheDocument();
+});

examples/EthiopicGeez.tsx

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+import React from "react";
+
+import { DayPicker } from "react-day-picker/ethiopic";
+
+export function EthiopicGeez() {
+  return <DayPicker numerals="geez" />;
+}

examples/index.ts

@@ -24,6 +24,7 @@ export * from "./DisableNavigation";
 export * from "./Dropdown";
 export * from "./DropdownMonths";
 export * from "./DropdownMultipleMonths";
+export * from "./Ethiopic";
 export * from "./Fixedweeks";
 export * from "./FocusRecursive";
 export * from "./FocusedDisabledNav";
@@ -57,6 +58,8 @@ export * from "./PastDatesDisabled";
 export * from "./Persian";
 export * from "./PersianFormatted";
 export * from "./PersianEn";
+export * from "./Ethiopic";
+export * from "./EthiopicGeez";
 export * from "./Range";
 export * from "./RangeExcludeDisabled";
 export * from "./RangeLong";

package.json

@@ -55,6 +55,16 @@
         "default": "./dist/cjs/persian.js"
       }
     },
+    "./ethiopic": {
+      "import": {
+        "types": "./dist/esm/ethiopic/index.d.ts",
+        "default": "./dist/esm/ethiopic/index.js"
+      },
+      "require": {
+        "types": "./dist/cjs/ethiopic/index.d.ts",
+        "default": "./dist/cjs/ethiopic/index.js"
+      }
+    },
     "./locale": {
       "import": {
         "types": "./dist/esm/locale.d.ts",

src/ethiopic/index.test.tsx

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+describe("DayPicker", () => {
+  test.todo("should render with default props");
+  test.todo("should render with custom locale");
+  test.todo("should render with custom numerals");
+});

src/ethiopic/index.tsx

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+import React from "react";
+
+import type { Locale } from "date-fns";
+
+import {
+  DateLib,
+  DateLibOptions,
+  DayPicker as DayPickerComponent
+} from "../index.js";
+import type { DayPickerProps } from "../types/props.js";
+
+import * as ethiopicDateLib from "./lib/index.js";
+
+/**
+ * Render the Ethiopic Calendar.
+ *
+ * @see https://daypicker.dev/docs/localization#ethiopic-calendar
+ */
+export function DayPicker(
+  props: DayPickerProps & {
+    /**
+     * The locale to use in the calendar.
+     *
+     * @default `am-ET`
+     */
+    locale?: Locale;
+    /**
+     * The numeral system to use when formatting dates.
+     *
+     * - `latn`: Latin (Western Arabic)
+     * - `geez`: Ge'ez (Ethiopic numerals)
+     *
+     * @defaultValue `latn` Latin (Western Arabic)
+     * @see https://daypicker.dev/docs/translation#numeral-systems
+     */
+    numerals?: DayPickerProps["numerals"];
+  }
+) {
+  const dateLib = getDateLib({
+    locale: props.locale,
+    weekStartsOn: 1,
+    firstWeekContainsDate: props.firstWeekContainsDate,
+    useAdditionalWeekYearTokens: props.useAdditionalWeekYearTokens,
+    useAdditionalDayOfYearTokens: props.useAdditionalDayOfYearTokens,
+    timeZone: props.timeZone
+  });
+  return (
+    <DayPickerComponent
+      {...props}
+      locale={props.locale ?? ({} as Locale)}
+      numerals={props.numerals ?? "latn"}
+      dateLib={dateLib}
+    />
+  );
+}
+
+/** Returns the date library used in the calendar. */
+export const getDateLib = (options?: DateLibOptions) => {
+  return new DateLib(options, ethiopicDateLib);
+};

src/ethiopic/lib/addMonths.test.ts

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+import { toEthiopicDate, toGregorianDate } from "../utils";
+
+import { addMonths } from "./addMonths";
+
+describe("addMonths", () => {
+  test("should add positive months correctly", () => {
+    // Test case 1: Adding within same year
+    const date1 = toGregorianDate({
+      year: 2016,
+      month: 4,
+      day: 22
+    }); // Greg: Jan 1, 2024
+    const result1 = addMonths(date1, 2);
+    const ethResult1 = toEthiopicDate(result1);
+    expect(ethResult1).toEqual({
+      year: 2016,
+      month: 6, // Yekatit(6)
+      day: 22
+    }); // Greg: Mar 1, 2024
+
+    // Test case 2: Adding across gregorian year boundary
+    const date2 = toGregorianDate({
+      year: 2016,
+      month: 5,
+      day: 22
+    }); // Greg: Feb 1, 2024
+    const result2 = addMonths(date2, 3);
+    const ethResult2 = toEthiopicDate(result2);
+    expect(ethResult2).toEqual({
+      year: 2016,
+      month: 8, // Meyazia(8)
+      day: 22
+    }); // Greg: Apr 30, 2024
+  });
+
+  test("should add negative months correctly", () => {
+    // Test case 1: Subtracting within same year
+    const date1 = toGregorianDate({
+      year: 2016,
+      month: 4,
+      day: 21
+    }); // Greg: Dec 31, 2023
+    const result1 = addMonths(date1, -2);
+    const ethResult1 = toEthiopicDate(result1);
+    expect(ethResult1).toEqual({
+      year: 2016,
+      month: 2, // Tikimt(2)
+      day: 21
+    }); // Greg: Oct 31, 2023
+
+    // Test case 2: Subtracting across gregorian year boundary
+    const date2 = toGregorianDate({
+      year: 2016,
+      month: 4,
+      day: 21
+    }); // Greg: Dec 31, 2023
+    const result2 = addMonths(date2, -3);
+    const ethResult2 = toEthiopicDate(result2);
+    expect(ethResult2).toEqual({
+      year: 2016,
+      month: 1, // Meskerem(1)
+      day: 21
+    }); // Greg: Oct 1, 2023
+  });
+
+  test("should handle day overflow in the 13th month Ethiopian calendar", () => {
+    // Test case 2: Day overflow in Pagume (13th month)
+    const date2 = toGregorianDate({
+      year: 2016,
+      month: 12,
+      day: 25
+    }); // Greg: Aug 31, 2024
+    const result2 = addMonths(date2, 1);
+    const ethResult2 = toEthiopicDate(result2);
+    expect(ethResult2).toEqual({
+      year: 2016,
+      month: 13, // Pagume
+      day: 5 // Adjusted from 26 to 5 (Pagume has only 5 or 6 days)
+    }); // Greg: Sep 5, 2024
+  });
+});

src/ethiopic/lib/addMonths.ts

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+import { daysInMonth } from "../utils/daysInMonth.js";
+import { toEthiopicDate, toGregorianDate } from "../utils/index.js";
+
+/**
+ * Adds the specified number of months to the given Ethiopian date. Handles
+ * month overflow and year boundaries correctly.
+ *
+ * @param date - The starting gregorian date
+ * @param amount - The number of months to add (can be negative)
+ * @returns A new gregorian date with the months added
+ */
+export function addMonths(date: Date, amount: number): Date {
+  const { year, month, day } = toEthiopicDate(date);
+  let newMonth = month + amount;
+  const yearAdjustment = Math.floor((newMonth - 1) / 13);
+  newMonth = ((newMonth - 1) % 13) + 1;
+
+  if (newMonth < 1) {
+    newMonth += 13;
+  }
+
+  const newYear = year + yearAdjustment;
+
+  // Adjust day if it exceeds the month length
+  const monthLength = daysInMonth(newMonth, newYear);
+  const newDay = Math.min(day, monthLength);
+
+  return toGregorianDate({ year: newYear, month: newMonth, day: newDay });
+}

src/ethiopic/lib/addYears.test.ts

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+import { toEthiopicDate, toGregorianDate } from "../utils/index.js";
+
+import { addYears } from "./addYears";
+
+describe("addYears", () => {
+  test("should add positive years correctly", () => {
+    const date = toGregorianDate({
+      year: 2015,
+      month: 4,
+      day: 22
+    }); // Greg: Jan 1, 2023
+    const result = addYears(date, 2);
+    const ethResult = toEthiopicDate(result);
+    expect(ethResult).toEqual({
+      year: 2017,
+      month: 4, // Tahsas(4)
+      day: 22
+    }); // Greg: Jan 1, 2025
+  });
+
+  test("should add negative years correctly", () => {
+    const date = toGregorianDate({
+      year: 2016,
+      month: 4,
+      day: 21
+    }); // Greg: Dec 31, 2023
+    const result = addYears(date, -2);
+    const ethResult = toEthiopicDate(result);
+    expect(ethResult).toEqual({
+      year: 2014,
+      month: 4, // Tahsas(4)
+      day: 21
+    }); // Greg: Dec 31, 2021
+  });
+
+  test("should maintain month and day when adding years from leap year", () => {
+    const date = toGregorianDate({
+      year: 2015,
+      month: 13, // Pagume
+      day: 6
+    }); // Greg: Sep 6, 2023, Leap year day
+    const result = addYears(date, 1);
+    const ethResult = toEthiopicDate(result);
+    expect(ethResult).toEqual({
+      year: 2016,
+      month: 13, // Pagume
+      day: 5
+    }); // Greg: Sep 6, 2024
+  });
+});

src/ethiopic/lib/addYears.ts

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+import {
+  isEthiopicLeapYear,
+  toEthiopicDate,
+  toGregorianDate
+} from "../utils/index.js";
+
+/**
+ * Adds the specified number of years to the given Ethiopian date. Handles leap
+ * year transitions for Pagume month.
+ *
+ * @param date - The starting gregorian date
+ * @param amount - The number of years to add (can be negative)
+ * @returns A new gregorian date with the years added
+ */
+export function addYears(date: Date, amount: number): Date {
+  const etDate = toEthiopicDate(date);
+  const day =
+    isEthiopicLeapYear(etDate.year) &&
+    etDate.month === 13 &&
+    etDate.day === 6 &&
+    amount % 4 !== 0
+      ? 5
+      : etDate.day;
+  return toGregorianDate({
+    month: etDate.month,
+    day: day,
+    year: etDate.year + amount
+  });
+}