refactor: code quality improvements across the board

2026-06-30 18:54:27 +00:00 · 2026-03-08 11:38:10 -04:00 · 2026-03-08 11:38:10 -04:00 · f0757b1333
commit f0757b1333
parent 0727665eaa
22 changed files with 2382 additions and 968 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -22,8 +22,22 @@ jobs:
          cache: pnpm
      - run: pnpm install --frozen-lockfile
      - run: pnpm run build
-      - run: node test.mjs
-      - run: node test-cjs.cjs
+      - run: node --test test.mjs
+      - run: node --test test-cjs.cjs
+
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm run lint
+      - run: pnpm run format:check

  typecheck:
    name: Typecheck
--- a/.gitignore
+++ b/.gitignore
@ -1,8 +1,30 @@
 node_modules/
 dist/
+build/
+out/
 *.tgz
+*.tsbuildinfo
 *.log
+npm-debug.log*
+coverage/
 .DS_Store
-.claude/
 .env
 .env.*
+!.env.example
+.claude/
+.vscode/
+.idea/
+*.swp
+.pnp
+.pnp.js
+.cursor/
+.copilot/
+.aider*
+.continue/
+.codex/
+.gemini/
+.vscode/*
+.aider/
+.aider.chat.history.md
+.windsurf/
+.codeium/
--- a/.prettierrc
+++ b/.prettierrc
@ -0,0 +1,6 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 100,
+  "tabWidth": 2
+}
--- a/.wiki/API-Reference.md
+++ b/.wiki/API-Reference.md
@ -7,12 +7,12 @@
 Converts a Gregorian `Date` to a Hijri date object.

 ```typescript
-function toHijri(date: Date, options?: ConversionOptions): HijriDate | null
+function toHijri(date: Date, options?: ConversionOptions): HijriDate | null;
 ```

-| Parameter | Type | Description |
-| --- | --- | --- |
-| `date` | `Date` | Gregorian date to convert |
+| Parameter          | Type     | Description                        |
+| ------------------ | -------- | ---------------------------------- |
+| `date`             | `Date`   | Gregorian date to convert          |
 | `options.calendar` | `string` | Calendar name. Defaults to `'uaq'` |

 Returns `HijriDate` or `null` if the date falls outside the calendar's supported range.
@ -26,19 +26,14 @@ UAQ uses local date components (`getFullYear`, `getMonth`, `getDate`) for timezo
 Converts a Hijri date to a Gregorian `Date`.

 ```typescript
-function toGregorian(
-  hy: number,
-  hm: number,
-  hd: number,
-  options?: ConversionOptions
-): Date | null
+function toGregorian(hy: number, hm: number, hd: number, options?: ConversionOptions): Date | null;
 ```

-| Parameter | Type | Description |
-| --- | --- | --- |
-| `hy` | `number` | Hijri year |
-| `hm` | `number` | Hijri month (1-12) |
-| `hd` | `number` | Hijri day (1-30) |
+| Parameter          | Type     | Description                        |
+| ------------------ | -------- | ---------------------------------- |
+| `hy`               | `number` | Hijri year                         |
+| `hm`               | `number` | Hijri month (1-12)                 |
+| `hd`               | `number` | Hijri day (1-30)                   |
 | `options.calendar` | `string` | Calendar name. Defaults to `'uaq'` |

 Returns a UTC midnight `Date` or `null` if the input is out of range.
@ -50,12 +45,7 @@ Throws `Error('Invalid Hijri date')` for UAQ when the date is not in the referen
 Returns `true` if the given Hijri date exists in the selected calendar.

 ```typescript
-function isValidHijriDate(
-  hy: number,
-  hm: number,
-  hd: number,
-  options?: ConversionOptions
-): boolean
+function isValidHijriDate(hy: number, hm: number, hd: number, options?: ConversionOptions): boolean;
 ```

 ### `daysInHijriMonth(hy, hm, options?)`
@ -63,7 +53,7 @@ function isValidHijriDate(
 Returns the number of days in a given Hijri month.

 ```typescript
-function daysInHijriMonth(hy: number, hm: number, options?: ConversionOptions): number
+function daysInHijriMonth(hy: number, hm: number, options?: ConversionOptions): number;
 ```

 Returns 29 or 30. Returns 0 for UAQ when the year is out of range.
@ -75,7 +65,7 @@ Returns 29 or 30. Returns 0 for UAQ when the year is out of range.
 Registers a calendar engine. Overwrites any existing engine with the same name.

 ```typescript
-function registerCalendar(name: string, engine: CalendarEngine): void
+function registerCalendar(name: string, engine: CalendarEngine): void;
 ```

 ### `getCalendar(name)`
@ -83,7 +73,7 @@ function registerCalendar(name: string, engine: CalendarEngine): void
 Returns the registered engine for a given name. Throws if not found.

 ```typescript
-function getCalendar(name: string): CalendarEngine
+function getCalendar(name: string): CalendarEngine;
 ```

 Throws `Error('Unknown Hijri calendar: "name". Available: ...')`.
@ -93,7 +83,7 @@ Throws `Error('Unknown Hijri calendar: "name". Available: ...')`.
 Returns the names of all registered calendars.

 ```typescript
-function listCalendars(): string[]
+function listCalendars(): string[];
 ```

 ## Types
@ -114,11 +104,11 @@ One entry in the Umm al-Qura reference table.

 ```typescript
 interface HijriYearRecord {
-  hy:  number; // Hijri year
+  hy: number; // Hijri year
  dpm: number; // 12-bit days-per-month bitmask
-  gy:  number; // Gregorian year of 1 Muharram
-  gm:  number; // Gregorian month of 1 Muharram (1-based)
-  gd:  number; // Gregorian day of 1 Muharram
+  gy: number; // Gregorian year of 1 Muharram
+  gm: number; // Gregorian month of 1 Muharram (1-based)
+  gd: number; // Gregorian day of 1 Muharram
 }
 ```

@ -146,15 +136,15 @@ interface ConversionOptions {

 ## Data exports

-| Export | Type | Description |
-| --- | --- | --- |
+| Export        | Type                | Description                                             |
+| ------------- | ------------------- | ------------------------------------------------------- |
 | `hDatesTable` | `HijriYearRecord[]` | Full UAQ table, 184 entries (1318-1500 H) plus sentinel |
-| `hmLong` | `string[]` | Long month names. Index 0 = Muharram |
-| `hmMedium` | `string[]` | Medium month names |
-| `hmShort` | `string[]` | Short month codes (3 chars) |
-| `hwLong` | `string[]` | Long weekday names. Index 0 = Sunday |
-| `hwShort` | `string[]` | Short weekday names |
-| `hwNumeric` | `number[]` | Weekday numbers, 1 = Sunday, 7 = Saturday |
+| `hmLong`      | `string[]`          | Long month names. Index 0 = Muharram                    |
+| `hmMedium`    | `string[]`          | Medium month names                                      |
+| `hmShort`     | `string[]`          | Short month codes (3 chars)                             |
+| `hwLong`      | `string[]`          | Long weekday names. Index 0 = Sunday                    |
+| `hwShort`     | `string[]`          | Short weekday names                                     |
+| `hwNumeric`   | `number[]`          | Weekday numbers, 1 = Sunday, 7 = Saturday               |

 ---

--- a/.wiki/Architecture.md
+++ b/.wiki/Architecture.md
@ -39,6 +39,7 @@ The Umm al-Qura calendar is the official Islamic calendar of Saudi Arabia. Month
 ### Data format

 Each `HijriYearRecord` stores:
+
 - The Gregorian date of 1 Muharram for that Hijri year
 - A 12-bit `dpm` bitmask: bit `i` (0-indexed) = month length for month `i+1`. Bit 1 = 30 days, bit 0 = 29 days

@ -70,9 +71,11 @@ The Fiqh Council of North America uses a global astronomical criterion rather th
 ### Criterion

 If the new moon conjunction occurs before 12:00 noon UTC on calendar day D:
+
 - The new Hijri month begins at midnight starting day D+1.

 If at or after 12:00 noon UTC:
+
 - The new Hijri month begins at midnight starting day D+2.

 This makes every Hijri month start deterministic from the astronomical conjunction time.
@ -111,11 +114,11 @@ import { registerCalendar, type CalendarEngine } from 'hijri-core';
 // A fixed-offset arithmetic calendar (not accurate, for illustration only).
 function hijriFromMs(ms: number) {
  const HIJRI_EPOCH_MS = -42521974440000; // approx
-  const MEAN_MONTH_MS  = 29.530588861 * 86_400_000;
+  const MEAN_MONTH_MS = 29.530588861 * 86_400_000;
  const months = Math.floor((ms - HIJRI_EPOCH_MS) / MEAN_MONTH_MS);
-  const hy     = Math.floor(months / 12) + 1;
-  const hm     = (months % 12) + 1;
-  const hd     = Math.floor(((ms - HIJRI_EPOCH_MS) % MEAN_MONTH_MS) / 86_400_000) + 1;
+  const hy = Math.floor(months / 12) + 1;
+  const hm = (months % 12) + 1;
+  const hd = Math.floor(((ms - HIJRI_EPOCH_MS) % MEAN_MONTH_MS) / 86_400_000) + 1;
  return { hy, hm: hm <= 0 ? hm + 12 : hm, hd };
 }

@ -124,7 +127,7 @@ const arithmeticEngine: CalendarEngine = {
  toHijri: (date) => hijriFromMs(date.getTime()),
  toGregorian: (hy, hm, hd) => null, // left as an exercise
  isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1 && hd <= 30,
-  daysInMonth: (hy, hm) => (hm % 2 === 1 || hm === 12) ? 30 : 29,
+  daysInMonth: (hy, hm) => (hm % 2 === 1 || hm === 12 ? 30 : 29),
 };

 registerCalendar('arithmetic', arithmeticEngine);
--- a/.wiki/Home.md
+++ b/.wiki/Home.md
@ -18,7 +18,7 @@ const greg = toGregorian(1446, 9, 1);

 // FCNA
 const hijriFcna = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
-const gregFcna  = toGregorian(1446, 9, 1, { calendar: 'fcna' });
+const gregFcna = toGregorian(1446, 9, 1, { calendar: 'fcna' });
 ```

 ## Custom calendar registration
--- a/README.md
+++ b/README.md
@ -29,11 +29,11 @@ const greg = toGregorian(1446, 9, 1);

 // FCNA/ISNA calendar
 const hijriFcna = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
-const gregFcna  = toGregorian(1446, 9, 1, { calendar: 'fcna' });
+const gregFcna = toGregorian(1446, 9, 1, { calendar: 'fcna' });

 // Validation and month length
-isValidHijriDate(1444, 9, 1);  // true
-daysInHijriMonth(1444, 9);     // 29
+isValidHijriDate(1444, 9, 1); // true
+daysInHijriMonth(1444, 9); // 29
 ```

 ### Custom Calendar
@ -43,8 +43,12 @@ import { registerCalendar, toHijri, type CalendarEngine } from 'hijri-core';

 const myEngine: CalendarEngine = {
  id: 'my-calendar',
-  toHijri: (date) => { /* your logic */ return { hy: 1446, hm: 1, hd: 1 }; },
-  toGregorian: (hy, hm, hd) => { /* your logic */ return new Date(); },
+  toHijri: (date) => {
+    /* your logic */ return { hy: 1446, hm: 1, hd: 1 };
+  },
+  toGregorian: (hy, hm, hd) => {
+    /* your logic */ return new Date();
+  },
  isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1,
  daysInMonth: (hy, hm) => 30,
 };
@ -58,34 +62,34 @@ const result = toHijri(new Date(), { calendar: 'my-calendar' });

 ### Conversion functions

-| Function | Parameters | Returns | Notes |
-| --- | --- | --- | --- |
-| `toHijri(date, opts?)` | `Date`, `ConversionOptions?` | `HijriDate \| null` | Throws on invalid Date |
-| `toGregorian(hy, hm, hd, opts?)` | `number, number, number, ConversionOptions?` | `Date \| null` | Returns null on invalid input |
-| `isValidHijriDate(hy, hm, hd, opts?)` | `number, number, number, ConversionOptions?` | `boolean` | |
-| `daysInHijriMonth(hy, hm, opts?)` | `number, number, ConversionOptions?` | `number` | |
+| Function                              | Parameters                                   | Returns             | Notes                         |
+| ------------------------------------- | -------------------------------------------- | ------------------- | ----------------------------- |
+| `toHijri(date, opts?)`                | `Date`, `ConversionOptions?`                 | `HijriDate \| null` | Throws on invalid Date        |
+| `toGregorian(hy, hm, hd, opts?)`      | `number, number, number, ConversionOptions?` | `Date \| null`      | Returns null on invalid input |
+| `isValidHijriDate(hy, hm, hd, opts?)` | `number, number, number, ConversionOptions?` | `boolean`           |                               |
+| `daysInHijriMonth(hy, hm, opts?)`     | `number, number, ConversionOptions?`         | `number`            |                               |

 `ConversionOptions.calendar` defaults to `'uaq'`. Pass `'fcna'` or any registered calendar name.

 ### Registry functions

-| Function | Parameters | Returns |
-| --- | --- | --- |
-| `registerCalendar(name, engine)` | `string, CalendarEngine` | `void` |
-| `getCalendar(name)` | `string` | `CalendarEngine` |
-| `listCalendars()` | none | `string[]` |
+| Function                         | Parameters               | Returns          |
+| -------------------------------- | ------------------------ | ---------------- |
+| `registerCalendar(name, engine)` | `string, CalendarEngine` | `void`           |
+| `getCalendar(name)`              | `string`                 | `CalendarEngine` |
+| `listCalendars()`                | none                     | `string[]`       |

 ### Data exports

-| Export | Type | Description |
-| --- | --- | --- |
+| Export        | Type                | Description                                    |
+| ------------- | ------------------- | ---------------------------------------------- |
 | `hDatesTable` | `HijriYearRecord[]` | Full Umm al-Qura reference table (184 entries) |
-| `hmLong` | `string[]` | Long month names (e.g., "Ramadan") |
-| `hmMedium` | `string[]` | Medium month names (e.g., "Ramadan") |
-| `hmShort` | `string[]` | Short month names (e.g., "Ram") |
-| `hwLong` | `string[]` | Long weekday names |
-| `hwShort` | `string[]` | Short weekday names |
-| `hwNumeric` | `number[]` | Weekday numbers (1 = Sunday) |
+| `hmLong`      | `string[]`          | Long month names (e.g., "Ramadan")             |
+| `hmMedium`    | `string[]`          | Medium month names (e.g., "Ramadan")           |
+| `hmShort`     | `string[]`          | Short month names (e.g., "Ram")                |
+| `hwLong`      | `string[]`          | Long weekday names                             |
+| `hwShort`     | `string[]`          | Short weekday names                            |
+| `hwNumeric`   | `number[]`          | Weekday numbers (1 = Sunday)                   |

 ## Custom Calendars

--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@ -0,0 +1,10 @@
+import js from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import prettier from 'eslint-config-prettier';
+
+export default tseslint.config(
+  { ignores: ['dist/', 'node_modules/', '*.cjs', '*.mjs'] },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  prettier,
+);
--- a/package.json
+++ b/package.json
@ -9,11 +9,20 @@
  "types": "./dist/index.d.ts",
  "exports": {
    ".": {
-      "import": { "types": "./dist/index.d.mts", "default": "./dist/index.mjs" },
-      "require": { "types": "./dist/index.d.ts", "default": "./dist/index.cjs" }
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.ts",
+        "default": "./dist/index.cjs"
+      }
    }
  },
-  "sideEffects": ["./dist/index.cjs", "./dist/index.mjs"],
+  "sideEffects": [
+    "./dist/index.cjs",
+    "./dist/index.mjs"
+  ],
  "files": [
    "dist/index.cjs",
    "dist/index.mjs",
@ -23,14 +32,19 @@
    "CHANGELOG.md",
    "LICENSE"
  ],
-  "engines": { "node": ">=20" },
+  "engines": {
+    "node": ">=20"
+  },
  "packageManager": "pnpm@10.30.1",
  "scripts": {
    "build": "tsup",
    "typecheck": "tsc --noEmit",
    "pretest": "tsup",
-    "test": "node test.mjs && node test-cjs.cjs",
-    "prepublishOnly": "tsup"
+    "test": "node --test test.mjs && node --test test-cjs.cjs",
+    "prepublishOnly": "tsup",
+    "lint": "eslint .",
+    "format": "prettier --write .",
+    "format:check": "prettier --check ."
  },
  "keywords": [
    "hijri",
@ -45,12 +59,25 @@
    "typescript"
  ],
  "devDependencies": {
-    "@types/node": "^22.0.0",
+    "@eslint/js": "^10.0.1",
+    "@types/node": "^22.15.0",
+    "eslint": "^10.0.3",
+    "eslint-config-prettier": "^10.1.8",
+    "prettier": "^3.8.1",
    "tsup": "^8.0.0",
-    "typescript": "^5.5.0"
+    "typescript": "^5.5.0",
+    "typescript-eslint": "^8.56.1"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/acamarata/hijri-core.git"
  },
-  "publishConfig": { "access": "public", "registry": "https://registry.npmjs.org/" },
-  "repository": { "type": "git", "url": "git+https://github.com/acamarata/hijri-core.git" },
  "homepage": "https://github.com/acamarata/hijri-core#readme",
-  "bugs": { "url": "https://github.com/acamarata/hijri-core/issues" }
+  "bugs": {
+    "url": "https://github.com/acamarata/hijri-core/issues"
+  }
 }
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
--- a/src/constants.ts
+++ b/src/constants.ts
@ -0,0 +1,5 @@
+/** Milliseconds in one day. */
+export const MS_PER_DAY = 86_400_000;
+
+/** Number of months in a Hijri year. */
+export const MONTHS_PER_YEAR = 12;
--- a/src/data/hDates.ts
+++ b/src/data/hDates.ts
@ -5,188 +5,188 @@ import type { HijriYearRecord } from '../types';
 // bitmask. Bit i (0-indexed from bit 0) corresponds to month i+1: 1 = 30 days,
 // 0 = 29 days. The final sentinel entry (hy 1501, dpm 0) marks the upper bound.
 export const hDatesTable: HijriYearRecord[] = [
-  { hy: 1318, dpm: 0x02EA, gy: 1900, gm:  4, gd: 30 },
-  { hy: 1319, dpm: 0x06E9, gy: 1901, gm:  4, gd: 19 },
-  { hy: 1320, dpm: 0x0ED2, gy: 1902, gm:  4, gd:  9 },
-  { hy: 1321, dpm: 0x0EA4, gy: 1903, gm:  3, gd: 30 },
-  { hy: 1322, dpm: 0x0D4A, gy: 1904, gm:  3, gd: 18 },
-  { hy: 1323, dpm: 0x0A96, gy: 1905, gm:  3, gd:  7 },
-  { hy: 1324, dpm: 0x0536, gy: 1906, gm:  2, gd: 24 },
-  { hy: 1325, dpm: 0x0AB5, gy: 1907, gm:  2, gd: 13 },
-  { hy: 1326, dpm: 0x0DAA, gy: 1908, gm:  2, gd:  3 },
-  { hy: 1327, dpm: 0x0BA4, gy: 1909, gm:  1, gd: 23 },
-  { hy: 1328, dpm: 0x0B49, gy: 1910, gm:  1, gd: 12 },
-  { hy: 1329, dpm: 0x0A93, gy: 1911, gm:  1, gd:  1 },
-  { hy: 1330, dpm: 0x052B, gy: 1911, gm: 12, gd: 21 },
-  { hy: 1331, dpm: 0x0A57, gy: 1912, gm: 12, gd:  9 },
-  { hy: 1332, dpm: 0x04B6, gy: 1913, gm: 11, gd: 29 },
-  { hy: 1333, dpm: 0x0AB5, gy: 1914, gm: 11, gd: 18 },
-  { hy: 1334, dpm: 0x05AA, gy: 1915, gm: 11, gd:  8 },
-  { hy: 1335, dpm: 0x0D55, gy: 1916, gm: 10, gd: 27 },
-  { hy: 1336, dpm: 0x0D2A, gy: 1917, gm: 10, gd: 17 },
-  { hy: 1337, dpm: 0x0A56, gy: 1918, gm: 10, gd:  6 },
-  { hy: 1338, dpm: 0x04AE, gy: 1919, gm:  9, gd: 25 },
-  { hy: 1339, dpm: 0x095D, gy: 1920, gm:  9, gd: 13 },
-  { hy: 1340, dpm: 0x02EC, gy: 1921, gm:  9, gd:  3 },
-  { hy: 1341, dpm: 0x06D5, gy: 1922, gm:  8, gd: 23 },
-  { hy: 1342, dpm: 0x06AA, gy: 1923, gm:  8, gd: 13 },
-  { hy: 1343, dpm: 0x0555, gy: 1924, gm:  8, gd:  1 },
-  { hy: 1344, dpm: 0x04AB, gy: 1925, gm:  7, gd: 21 },
-  { hy: 1345, dpm: 0x095B, gy: 1926, gm:  7, gd: 10 },
-  { hy: 1346, dpm: 0x02BA, gy: 1927, gm:  6, gd: 30 },
-  { hy: 1347, dpm: 0x0575, gy: 1928, gm:  6, gd: 18 },
-  { hy: 1348, dpm: 0x0BB2, gy: 1929, gm:  6, gd:  8 },
-  { hy: 1349, dpm: 0x0764, gy: 1930, gm:  5, gd: 29 },
-  { hy: 1350, dpm: 0x0749, gy: 1931, gm:  5, gd: 18 },
-  { hy: 1351, dpm: 0x0655, gy: 1932, gm:  5, gd:  6 },
-  { hy: 1352, dpm: 0x02AB, gy: 1933, gm:  4, gd: 25 },
-  { hy: 1353, dpm: 0x055B, gy: 1934, gm:  4, gd: 14 },
-  { hy: 1354, dpm: 0x0ADA, gy: 1935, gm:  4, gd:  4 },
-  { hy: 1355, dpm: 0x06D4, gy: 1936, gm:  3, gd: 24 },
-  { hy: 1356, dpm: 0x0EC9, gy: 1937, gm:  3, gd: 13 },
-  { hy: 1357, dpm: 0x0D92, gy: 1938, gm:  3, gd:  3 },
-  { hy: 1358, dpm: 0x0D25, gy: 1939, gm:  2, gd: 20 },
-  { hy: 1359, dpm: 0x0A4D, gy: 1940, gm:  2, gd:  9 },
-  { hy: 1360, dpm: 0x02AD, gy: 1941, gm:  1, gd: 28 },
-  { hy: 1361, dpm: 0x056D, gy: 1942, gm:  1, gd: 17 },
-  { hy: 1362, dpm: 0x0B6A, gy: 1943, gm:  1, gd:  7 },
-  { hy: 1363, dpm: 0x0B52, gy: 1943, gm: 12, gd: 28 },
-  { hy: 1364, dpm: 0x0AA5, gy: 1944, gm: 12, gd: 16 },
-  { hy: 1365, dpm: 0x0A4B, gy: 1945, gm: 12, gd:  5 },
+  { hy: 1318, dpm: 0x02ea, gy: 1900, gm: 4, gd: 30 },
+  { hy: 1319, dpm: 0x06e9, gy: 1901, gm: 4, gd: 19 },
+  { hy: 1320, dpm: 0x0ed2, gy: 1902, gm: 4, gd: 9 },
+  { hy: 1321, dpm: 0x0ea4, gy: 1903, gm: 3, gd: 30 },
+  { hy: 1322, dpm: 0x0d4a, gy: 1904, gm: 3, gd: 18 },
+  { hy: 1323, dpm: 0x0a96, gy: 1905, gm: 3, gd: 7 },
+  { hy: 1324, dpm: 0x0536, gy: 1906, gm: 2, gd: 24 },
+  { hy: 1325, dpm: 0x0ab5, gy: 1907, gm: 2, gd: 13 },
+  { hy: 1326, dpm: 0x0daa, gy: 1908, gm: 2, gd: 3 },
+  { hy: 1327, dpm: 0x0ba4, gy: 1909, gm: 1, gd: 23 },
+  { hy: 1328, dpm: 0x0b49, gy: 1910, gm: 1, gd: 12 },
+  { hy: 1329, dpm: 0x0a93, gy: 1911, gm: 1, gd: 1 },
+  { hy: 1330, dpm: 0x052b, gy: 1911, gm: 12, gd: 21 },
+  { hy: 1331, dpm: 0x0a57, gy: 1912, gm: 12, gd: 9 },
+  { hy: 1332, dpm: 0x04b6, gy: 1913, gm: 11, gd: 29 },
+  { hy: 1333, dpm: 0x0ab5, gy: 1914, gm: 11, gd: 18 },
+  { hy: 1334, dpm: 0x05aa, gy: 1915, gm: 11, gd: 8 },
+  { hy: 1335, dpm: 0x0d55, gy: 1916, gm: 10, gd: 27 },
+  { hy: 1336, dpm: 0x0d2a, gy: 1917, gm: 10, gd: 17 },
+  { hy: 1337, dpm: 0x0a56, gy: 1918, gm: 10, gd: 6 },
+  { hy: 1338, dpm: 0x04ae, gy: 1919, gm: 9, gd: 25 },
+  { hy: 1339, dpm: 0x095d, gy: 1920, gm: 9, gd: 13 },
+  { hy: 1340, dpm: 0x02ec, gy: 1921, gm: 9, gd: 3 },
+  { hy: 1341, dpm: 0x06d5, gy: 1922, gm: 8, gd: 23 },
+  { hy: 1342, dpm: 0x06aa, gy: 1923, gm: 8, gd: 13 },
+  { hy: 1343, dpm: 0x0555, gy: 1924, gm: 8, gd: 1 },
+  { hy: 1344, dpm: 0x04ab, gy: 1925, gm: 7, gd: 21 },
+  { hy: 1345, dpm: 0x095b, gy: 1926, gm: 7, gd: 10 },
+  { hy: 1346, dpm: 0x02ba, gy: 1927, gm: 6, gd: 30 },
+  { hy: 1347, dpm: 0x0575, gy: 1928, gm: 6, gd: 18 },
+  { hy: 1348, dpm: 0x0bb2, gy: 1929, gm: 6, gd: 8 },
+  { hy: 1349, dpm: 0x0764, gy: 1930, gm: 5, gd: 29 },
+  { hy: 1350, dpm: 0x0749, gy: 1931, gm: 5, gd: 18 },
+  { hy: 1351, dpm: 0x0655, gy: 1932, gm: 5, gd: 6 },
+  { hy: 1352, dpm: 0x02ab, gy: 1933, gm: 4, gd: 25 },
+  { hy: 1353, dpm: 0x055b, gy: 1934, gm: 4, gd: 14 },
+  { hy: 1354, dpm: 0x0ada, gy: 1935, gm: 4, gd: 4 },
+  { hy: 1355, dpm: 0x06d4, gy: 1936, gm: 3, gd: 24 },
+  { hy: 1356, dpm: 0x0ec9, gy: 1937, gm: 3, gd: 13 },
+  { hy: 1357, dpm: 0x0d92, gy: 1938, gm: 3, gd: 3 },
+  { hy: 1358, dpm: 0x0d25, gy: 1939, gm: 2, gd: 20 },
+  { hy: 1359, dpm: 0x0a4d, gy: 1940, gm: 2, gd: 9 },
+  { hy: 1360, dpm: 0x02ad, gy: 1941, gm: 1, gd: 28 },
+  { hy: 1361, dpm: 0x056d, gy: 1942, gm: 1, gd: 17 },
+  { hy: 1362, dpm: 0x0b6a, gy: 1943, gm: 1, gd: 7 },
+  { hy: 1363, dpm: 0x0b52, gy: 1943, gm: 12, gd: 28 },
+  { hy: 1364, dpm: 0x0aa5, gy: 1944, gm: 12, gd: 16 },
+  { hy: 1365, dpm: 0x0a4b, gy: 1945, gm: 12, gd: 5 },
  { hy: 1366, dpm: 0x0497, gy: 1946, gm: 11, gd: 24 },
  { hy: 1367, dpm: 0x0937, gy: 1947, gm: 11, gd: 13 },
-  { hy: 1368, dpm: 0x02B6, gy: 1948, gm: 11, gd:  2 },
+  { hy: 1368, dpm: 0x02b6, gy: 1948, gm: 11, gd: 2 },
  { hy: 1369, dpm: 0x0575, gy: 1949, gm: 10, gd: 22 },
-  { hy: 1370, dpm: 0x0D6A, gy: 1950, gm: 10, gd: 12 },
-  { hy: 1371, dpm: 0x0D52, gy: 1951, gm: 10, gd:  2 },
-  { hy: 1372, dpm: 0x0A96, gy: 1952, gm:  9, gd: 20 },
-  { hy: 1373, dpm: 0x092D, gy: 1953, gm:  9, gd:  9 },
-  { hy: 1374, dpm: 0x025D, gy: 1954, gm:  8, gd: 29 },
-  { hy: 1375, dpm: 0x04DD, gy: 1955, gm:  8, gd: 18 },
-  { hy: 1376, dpm: 0x0ADA, gy: 1956, gm:  8, gd:  7 },
-  { hy: 1377, dpm: 0x05D4, gy: 1957, gm:  7, gd: 28 },
-  { hy: 1378, dpm: 0x0DA9, gy: 1958, gm:  7, gd: 17 },
-  { hy: 1379, dpm: 0x0D52, gy: 1959, gm:  7, gd:  7 },
-  { hy: 1380, dpm: 0x0AAA, gy: 1960, gm:  6, gd: 25 },
-  { hy: 1381, dpm: 0x04D6, gy: 1961, gm:  6, gd: 14 },
-  { hy: 1382, dpm: 0x09B6, gy: 1962, gm:  6, gd:  3 },
-  { hy: 1383, dpm: 0x0374, gy: 1963, gm:  5, gd: 24 },
-  { hy: 1384, dpm: 0x0769, gy: 1964, gm:  5, gd: 12 },
-  { hy: 1385, dpm: 0x0752, gy: 1965, gm:  5, gd:  2 },
-  { hy: 1386, dpm: 0x06A5, gy: 1966, gm:  4, gd: 21 },
-  { hy: 1387, dpm: 0x054B, gy: 1967, gm:  4, gd: 10 },
-  { hy: 1388, dpm: 0x0AAB, gy: 1968, gm:  3, gd: 29 },
-  { hy: 1389, dpm: 0x055A, gy: 1969, gm:  3, gd: 19 },
-  { hy: 1390, dpm: 0x0AD5, gy: 1970, gm:  3, gd:  8 },
-  { hy: 1391, dpm: 0x0DD2, gy: 1971, gm:  2, gd: 26 },
-  { hy: 1392, dpm: 0x0DA4, gy: 1972, gm:  2, gd: 16 },
-  { hy: 1393, dpm: 0x0D49, gy: 1973, gm:  2, gd:  4 },
-  { hy: 1394, dpm: 0x0A95, gy: 1974, gm:  1, gd: 24 },
-  { hy: 1395, dpm: 0x052D, gy: 1975, gm:  1, gd: 13 },
-  { hy: 1396, dpm: 0x0A5D, gy: 1976, gm:  1, gd:  2 },
-  { hy: 1397, dpm: 0x055A, gy: 1976, gm: 12, gd: 22 },
-  { hy: 1398, dpm: 0x0AD5, gy: 1977, gm: 12, gd: 11 },
-  { hy: 1399, dpm: 0x06AA, gy: 1978, gm: 12, gd:  1 },
+  { hy: 1370, dpm: 0x0d6a, gy: 1950, gm: 10, gd: 12 },
+  { hy: 1371, dpm: 0x0d52, gy: 1951, gm: 10, gd: 2 },
+  { hy: 1372, dpm: 0x0a96, gy: 1952, gm: 9, gd: 20 },
+  { hy: 1373, dpm: 0x092d, gy: 1953, gm: 9, gd: 9 },
+  { hy: 1374, dpm: 0x025d, gy: 1954, gm: 8, gd: 29 },
+  { hy: 1375, dpm: 0x04dd, gy: 1955, gm: 8, gd: 18 },
+  { hy: 1376, dpm: 0x0ada, gy: 1956, gm: 8, gd: 7 },
+  { hy: 1377, dpm: 0x05d4, gy: 1957, gm: 7, gd: 28 },
+  { hy: 1378, dpm: 0x0da9, gy: 1958, gm: 7, gd: 17 },
+  { hy: 1379, dpm: 0x0d52, gy: 1959, gm: 7, gd: 7 },
+  { hy: 1380, dpm: 0x0aaa, gy: 1960, gm: 6, gd: 25 },
+  { hy: 1381, dpm: 0x04d6, gy: 1961, gm: 6, gd: 14 },
+  { hy: 1382, dpm: 0x09b6, gy: 1962, gm: 6, gd: 3 },
+  { hy: 1383, dpm: 0x0374, gy: 1963, gm: 5, gd: 24 },
+  { hy: 1384, dpm: 0x0769, gy: 1964, gm: 5, gd: 12 },
+  { hy: 1385, dpm: 0x0752, gy: 1965, gm: 5, gd: 2 },
+  { hy: 1386, dpm: 0x06a5, gy: 1966, gm: 4, gd: 21 },
+  { hy: 1387, dpm: 0x054b, gy: 1967, gm: 4, gd: 10 },
+  { hy: 1388, dpm: 0x0aab, gy: 1968, gm: 3, gd: 29 },
+  { hy: 1389, dpm: 0x055a, gy: 1969, gm: 3, gd: 19 },
+  { hy: 1390, dpm: 0x0ad5, gy: 1970, gm: 3, gd: 8 },
+  { hy: 1391, dpm: 0x0dd2, gy: 1971, gm: 2, gd: 26 },
+  { hy: 1392, dpm: 0x0da4, gy: 1972, gm: 2, gd: 16 },
+  { hy: 1393, dpm: 0x0d49, gy: 1973, gm: 2, gd: 4 },
+  { hy: 1394, dpm: 0x0a95, gy: 1974, gm: 1, gd: 24 },
+  { hy: 1395, dpm: 0x052d, gy: 1975, gm: 1, gd: 13 },
+  { hy: 1396, dpm: 0x0a5d, gy: 1976, gm: 1, gd: 2 },
+  { hy: 1397, dpm: 0x055a, gy: 1976, gm: 12, gd: 22 },
+  { hy: 1398, dpm: 0x0ad5, gy: 1977, gm: 12, gd: 11 },
+  { hy: 1399, dpm: 0x06aa, gy: 1978, gm: 12, gd: 1 },
  { hy: 1400, dpm: 0x0695, gy: 1979, gm: 11, gd: 20 },
-  { hy: 1401, dpm: 0x052B, gy: 1980, gm: 11, gd:  8 },
-  { hy: 1402, dpm: 0x0A57, gy: 1981, gm: 10, gd: 28 },
-  { hy: 1403, dpm: 0x04AE, gy: 1982, gm: 10, gd: 18 },
-  { hy: 1404, dpm: 0x0976, gy: 1983, gm: 10, gd:  7 },
-  { hy: 1405, dpm: 0x056C, gy: 1984, gm:  9, gd: 26 },
-  { hy: 1406, dpm: 0x0B55, gy: 1985, gm:  9, gd: 15 },
-  { hy: 1407, dpm: 0x0AAA, gy: 1986, gm:  9, gd:  5 },
-  { hy: 1408, dpm: 0x0A55, gy: 1987, gm:  8, gd: 25 },
-  { hy: 1409, dpm: 0x04AD, gy: 1988, gm:  8, gd: 13 },
-  { hy: 1410, dpm: 0x095D, gy: 1989, gm:  8, gd:  2 },
-  { hy: 1411, dpm: 0x02DA, gy: 1990, gm:  7, gd: 23 },
-  { hy: 1412, dpm: 0x05D9, gy: 1991, gm:  7, gd: 12 },
-  { hy: 1413, dpm: 0x0DB2, gy: 1992, gm:  7, gd:  1 },
-  { hy: 1414, dpm: 0x0BA4, gy: 1993, gm:  6, gd: 21 },
-  { hy: 1415, dpm: 0x0B4A, gy: 1994, gm:  6, gd: 10 },
-  { hy: 1416, dpm: 0x0A55, gy: 1995, gm:  5, gd: 30 },
-  { hy: 1417, dpm: 0x02B5, gy: 1996, gm:  5, gd: 18 },
-  { hy: 1418, dpm: 0x0575, gy: 1997, gm:  5, gd:  7 },
-  { hy: 1419, dpm: 0x0B6A, gy: 1998, gm:  4, gd: 27 },
-  { hy: 1420, dpm: 0x0BD2, gy: 1999, gm:  4, gd: 17 },
-  { hy: 1421, dpm: 0x0BC4, gy: 2000, gm:  4, gd:  6 },
-  { hy: 1422, dpm: 0x0B89, gy: 2001, gm:  3, gd: 26 },
-  { hy: 1423, dpm: 0x0A95, gy: 2002, gm:  3, gd: 15 },
-  { hy: 1424, dpm: 0x052D, gy: 2003, gm:  3, gd:  4 },
-  { hy: 1425, dpm: 0x05AD, gy: 2004, gm:  2, gd: 21 },
-  { hy: 1426, dpm: 0x0B6A, gy: 2005, gm:  2, gd: 10 },
-  { hy: 1427, dpm: 0x06D4, gy: 2006, gm:  1, gd: 31 },
-  { hy: 1428, dpm: 0x0DC9, gy: 2007, gm:  1, gd: 20 },
-  { hy: 1429, dpm: 0x0D92, gy: 2008, gm:  1, gd: 10 },
-  { hy: 1430, dpm: 0x0AA6, gy: 2008, gm: 12, gd: 29 },
+  { hy: 1401, dpm: 0x052b, gy: 1980, gm: 11, gd: 8 },
+  { hy: 1402, dpm: 0x0a57, gy: 1981, gm: 10, gd: 28 },
+  { hy: 1403, dpm: 0x04ae, gy: 1982, gm: 10, gd: 18 },
+  { hy: 1404, dpm: 0x0976, gy: 1983, gm: 10, gd: 7 },
+  { hy: 1405, dpm: 0x056c, gy: 1984, gm: 9, gd: 26 },
+  { hy: 1406, dpm: 0x0b55, gy: 1985, gm: 9, gd: 15 },
+  { hy: 1407, dpm: 0x0aaa, gy: 1986, gm: 9, gd: 5 },
+  { hy: 1408, dpm: 0x0a55, gy: 1987, gm: 8, gd: 25 },
+  { hy: 1409, dpm: 0x04ad, gy: 1988, gm: 8, gd: 13 },
+  { hy: 1410, dpm: 0x095d, gy: 1989, gm: 8, gd: 2 },
+  { hy: 1411, dpm: 0x02da, gy: 1990, gm: 7, gd: 23 },
+  { hy: 1412, dpm: 0x05d9, gy: 1991, gm: 7, gd: 12 },
+  { hy: 1413, dpm: 0x0db2, gy: 1992, gm: 7, gd: 1 },
+  { hy: 1414, dpm: 0x0ba4, gy: 1993, gm: 6, gd: 21 },
+  { hy: 1415, dpm: 0x0b4a, gy: 1994, gm: 6, gd: 10 },
+  { hy: 1416, dpm: 0x0a55, gy: 1995, gm: 5, gd: 30 },
+  { hy: 1417, dpm: 0x02b5, gy: 1996, gm: 5, gd: 18 },
+  { hy: 1418, dpm: 0x0575, gy: 1997, gm: 5, gd: 7 },
+  { hy: 1419, dpm: 0x0b6a, gy: 1998, gm: 4, gd: 27 },
+  { hy: 1420, dpm: 0x0bd2, gy: 1999, gm: 4, gd: 17 },
+  { hy: 1421, dpm: 0x0bc4, gy: 2000, gm: 4, gd: 6 },
+  { hy: 1422, dpm: 0x0b89, gy: 2001, gm: 3, gd: 26 },
+  { hy: 1423, dpm: 0x0a95, gy: 2002, gm: 3, gd: 15 },
+  { hy: 1424, dpm: 0x052d, gy: 2003, gm: 3, gd: 4 },
+  { hy: 1425, dpm: 0x05ad, gy: 2004, gm: 2, gd: 21 },
+  { hy: 1426, dpm: 0x0b6a, gy: 2005, gm: 2, gd: 10 },
+  { hy: 1427, dpm: 0x06d4, gy: 2006, gm: 1, gd: 31 },
+  { hy: 1428, dpm: 0x0dc9, gy: 2007, gm: 1, gd: 20 },
+  { hy: 1429, dpm: 0x0d92, gy: 2008, gm: 1, gd: 10 },
+  { hy: 1430, dpm: 0x0aa6, gy: 2008, gm: 12, gd: 29 },
  { hy: 1431, dpm: 0x0956, gy: 2009, gm: 12, gd: 18 },
-  { hy: 1432, dpm: 0x02AE, gy: 2010, gm: 12, gd:  7 },
-  { hy: 1433, dpm: 0x056D, gy: 2011, gm: 11, gd: 26 },
-  { hy: 1434, dpm: 0x036A, gy: 2012, gm: 11, gd: 15 },
-  { hy: 1435, dpm: 0x0B55, gy: 2013, gm: 11, gd:  4 },
-  { hy: 1436, dpm: 0x0AAA, gy: 2014, gm: 10, gd: 25 },
-  { hy: 1437, dpm: 0x094D, gy: 2015, gm: 10, gd: 14 },
-  { hy: 1438, dpm: 0x049D, gy: 2016, gm: 10, gd:  2 },
-  { hy: 1439, dpm: 0x095D, gy: 2017, gm:  9, gd: 21 },
-  { hy: 1440, dpm: 0x02BA, gy: 2018, gm:  9, gd: 11 },
-  { hy: 1441, dpm: 0x05B5, gy: 2019, gm:  8, gd: 31 },
-  { hy: 1442, dpm: 0x05AA, gy: 2020, gm:  8, gd: 20 },
-  { hy: 1443, dpm: 0x0D55, gy: 2021, gm:  8, gd:  9 },
-  { hy: 1444, dpm: 0x0A9A, gy: 2022, gm:  7, gd: 30 },
-  { hy: 1445, dpm: 0x092E, gy: 2023, gm:  7, gd: 19 },
-  { hy: 1446, dpm: 0x026E, gy: 2024, gm:  7, gd:  7 },
-  { hy: 1447, dpm: 0x055D, gy: 2025, gm:  6, gd: 26 },
-  { hy: 1448, dpm: 0x0ADA, gy: 2026, gm:  6, gd: 16 },
-  { hy: 1449, dpm: 0x06D4, gy: 2027, gm:  6, gd:  6 },
-  { hy: 1450, dpm: 0x06A5, gy: 2028, gm:  5, gd: 25 },
-  { hy: 1451, dpm: 0x054B, gy: 2029, gm:  5, gd: 14 },
-  { hy: 1452, dpm: 0x0A97, gy: 2030, gm:  5, gd:  3 },
-  { hy: 1453, dpm: 0x054E, gy: 2031, gm:  4, gd: 23 },
-  { hy: 1454, dpm: 0x0AAE, gy: 2032, gm:  4, gd: 11 },
-  { hy: 1455, dpm: 0x05AC, gy: 2033, gm:  4, gd:  1 },
-  { hy: 1456, dpm: 0x0BA9, gy: 2034, gm:  3, gd: 21 },
-  { hy: 1457, dpm: 0x0D92, gy: 2035, gm:  3, gd: 11 },
-  { hy: 1458, dpm: 0x0B25, gy: 2036, gm:  2, gd: 28 },
-  { hy: 1459, dpm: 0x064B, gy: 2037, gm:  2, gd: 16 },
-  { hy: 1460, dpm: 0x0CAB, gy: 2038, gm:  2, gd:  5 },
-  { hy: 1461, dpm: 0x055A, gy: 2039, gm:  1, gd: 26 },
-  { hy: 1462, dpm: 0x0B55, gy: 2040, gm:  1, gd: 15 },
-  { hy: 1463, dpm: 0x06D2, gy: 2041, gm:  1, gd:  4 },
-  { hy: 1464, dpm: 0x0EA5, gy: 2041, gm: 12, gd: 24 },
-  { hy: 1465, dpm: 0x0E4A, gy: 2042, gm: 12, gd: 14 },
-  { hy: 1466, dpm: 0x0A95, gy: 2043, gm: 12, gd:  3 },
-  { hy: 1467, dpm: 0x052D, gy: 2044, gm: 11, gd: 21 },
-  { hy: 1468, dpm: 0x0AAD, gy: 2045, gm: 11, gd: 10 },
-  { hy: 1469, dpm: 0x036C, gy: 2046, gm: 10, gd: 31 },
+  { hy: 1432, dpm: 0x02ae, gy: 2010, gm: 12, gd: 7 },
+  { hy: 1433, dpm: 0x056d, gy: 2011, gm: 11, gd: 26 },
+  { hy: 1434, dpm: 0x036a, gy: 2012, gm: 11, gd: 15 },
+  { hy: 1435, dpm: 0x0b55, gy: 2013, gm: 11, gd: 4 },
+  { hy: 1436, dpm: 0x0aaa, gy: 2014, gm: 10, gd: 25 },
+  { hy: 1437, dpm: 0x094d, gy: 2015, gm: 10, gd: 14 },
+  { hy: 1438, dpm: 0x049d, gy: 2016, gm: 10, gd: 2 },
+  { hy: 1439, dpm: 0x095d, gy: 2017, gm: 9, gd: 21 },
+  { hy: 1440, dpm: 0x02ba, gy: 2018, gm: 9, gd: 11 },
+  { hy: 1441, dpm: 0x05b5, gy: 2019, gm: 8, gd: 31 },
+  { hy: 1442, dpm: 0x05aa, gy: 2020, gm: 8, gd: 20 },
+  { hy: 1443, dpm: 0x0d55, gy: 2021, gm: 8, gd: 9 },
+  { hy: 1444, dpm: 0x0a9a, gy: 2022, gm: 7, gd: 30 },
+  { hy: 1445, dpm: 0x092e, gy: 2023, gm: 7, gd: 19 },
+  { hy: 1446, dpm: 0x026e, gy: 2024, gm: 7, gd: 7 },
+  { hy: 1447, dpm: 0x055d, gy: 2025, gm: 6, gd: 26 },
+  { hy: 1448, dpm: 0x0ada, gy: 2026, gm: 6, gd: 16 },
+  { hy: 1449, dpm: 0x06d4, gy: 2027, gm: 6, gd: 6 },
+  { hy: 1450, dpm: 0x06a5, gy: 2028, gm: 5, gd: 25 },
+  { hy: 1451, dpm: 0x054b, gy: 2029, gm: 5, gd: 14 },
+  { hy: 1452, dpm: 0x0a97, gy: 2030, gm: 5, gd: 3 },
+  { hy: 1453, dpm: 0x054e, gy: 2031, gm: 4, gd: 23 },
+  { hy: 1454, dpm: 0x0aae, gy: 2032, gm: 4, gd: 11 },
+  { hy: 1455, dpm: 0x05ac, gy: 2033, gm: 4, gd: 1 },
+  { hy: 1456, dpm: 0x0ba9, gy: 2034, gm: 3, gd: 21 },
+  { hy: 1457, dpm: 0x0d92, gy: 2035, gm: 3, gd: 11 },
+  { hy: 1458, dpm: 0x0b25, gy: 2036, gm: 2, gd: 28 },
+  { hy: 1459, dpm: 0x064b, gy: 2037, gm: 2, gd: 16 },
+  { hy: 1460, dpm: 0x0cab, gy: 2038, gm: 2, gd: 5 },
+  { hy: 1461, dpm: 0x055a, gy: 2039, gm: 1, gd: 26 },
+  { hy: 1462, dpm: 0x0b55, gy: 2040, gm: 1, gd: 15 },
+  { hy: 1463, dpm: 0x06d2, gy: 2041, gm: 1, gd: 4 },
+  { hy: 1464, dpm: 0x0ea5, gy: 2041, gm: 12, gd: 24 },
+  { hy: 1465, dpm: 0x0e4a, gy: 2042, gm: 12, gd: 14 },
+  { hy: 1466, dpm: 0x0a95, gy: 2043, gm: 12, gd: 3 },
+  { hy: 1467, dpm: 0x052d, gy: 2044, gm: 11, gd: 21 },
+  { hy: 1468, dpm: 0x0aad, gy: 2045, gm: 11, gd: 10 },
+  { hy: 1469, dpm: 0x036c, gy: 2046, gm: 10, gd: 31 },
  { hy: 1470, dpm: 0x0759, gy: 2047, gm: 10, gd: 20 },
-  { hy: 1471, dpm: 0x06D2, gy: 2048, gm: 10, gd:  9 },
-  { hy: 1472, dpm: 0x0695, gy: 2049, gm:  9, gd: 28 },
-  { hy: 1473, dpm: 0x052D, gy: 2050, gm:  9, gd: 17 },
-  { hy: 1474, dpm: 0x0A5B, gy: 2051, gm:  9, gd:  6 },
-  { hy: 1475, dpm: 0x04BA, gy: 2052, gm:  8, gd: 26 },
-  { hy: 1476, dpm: 0x09BA, gy: 2053, gm:  8, gd: 15 },
-  { hy: 1477, dpm: 0x03B4, gy: 2054, gm:  8, gd:  5 },
-  { hy: 1478, dpm: 0x0B69, gy: 2055, gm:  7, gd: 25 },
-  { hy: 1479, dpm: 0x0B52, gy: 2056, gm:  7, gd: 14 },
-  { hy: 1480, dpm: 0x0AA6, gy: 2057, gm:  7, gd:  3 },
-  { hy: 1481, dpm: 0x04B6, gy: 2058, gm:  6, gd: 22 },
-  { hy: 1482, dpm: 0x096D, gy: 2059, gm:  6, gd: 11 },
-  { hy: 1483, dpm: 0x02EC, gy: 2060, gm:  5, gd: 31 },
-  { hy: 1484, dpm: 0x06D9, gy: 2061, gm:  5, gd: 20 },
-  { hy: 1485, dpm: 0x0EB2, gy: 2062, gm:  5, gd: 10 },
-  { hy: 1486, dpm: 0x0D54, gy: 2063, gm:  4, gd: 30 },
-  { hy: 1487, dpm: 0x0D2A, gy: 2064, gm:  4, gd: 18 },
-  { hy: 1488, dpm: 0x0A56, gy: 2065, gm:  4, gd:  7 },
-  { hy: 1489, dpm: 0x04AE, gy: 2066, gm:  3, gd: 27 },
-  { hy: 1490, dpm: 0x096D, gy: 2067, gm:  3, gd: 16 },
-  { hy: 1491, dpm: 0x0D6A, gy: 2068, gm:  3, gd:  5 },
-  { hy: 1492, dpm: 0x0B54, gy: 2069, gm:  2, gd: 23 },
-  { hy: 1493, dpm: 0x0B29, gy: 2070, gm:  2, gd: 12 },
-  { hy: 1494, dpm: 0x0A93, gy: 2071, gm:  2, gd:  1 },
-  { hy: 1495, dpm: 0x052B, gy: 2072, gm:  1, gd: 21 },
-  { hy: 1496, dpm: 0x0A57, gy: 2073, gm:  1, gd:  9 },
+  { hy: 1471, dpm: 0x06d2, gy: 2048, gm: 10, gd: 9 },
+  { hy: 1472, dpm: 0x0695, gy: 2049, gm: 9, gd: 28 },
+  { hy: 1473, dpm: 0x052d, gy: 2050, gm: 9, gd: 17 },
+  { hy: 1474, dpm: 0x0a5b, gy: 2051, gm: 9, gd: 6 },
+  { hy: 1475, dpm: 0x04ba, gy: 2052, gm: 8, gd: 26 },
+  { hy: 1476, dpm: 0x09ba, gy: 2053, gm: 8, gd: 15 },
+  { hy: 1477, dpm: 0x03b4, gy: 2054, gm: 8, gd: 5 },
+  { hy: 1478, dpm: 0x0b69, gy: 2055, gm: 7, gd: 25 },
+  { hy: 1479, dpm: 0x0b52, gy: 2056, gm: 7, gd: 14 },
+  { hy: 1480, dpm: 0x0aa6, gy: 2057, gm: 7, gd: 3 },
+  { hy: 1481, dpm: 0x04b6, gy: 2058, gm: 6, gd: 22 },
+  { hy: 1482, dpm: 0x096d, gy: 2059, gm: 6, gd: 11 },
+  { hy: 1483, dpm: 0x02ec, gy: 2060, gm: 5, gd: 31 },
+  { hy: 1484, dpm: 0x06d9, gy: 2061, gm: 5, gd: 20 },
+  { hy: 1485, dpm: 0x0eb2, gy: 2062, gm: 5, gd: 10 },
+  { hy: 1486, dpm: 0x0d54, gy: 2063, gm: 4, gd: 30 },
+  { hy: 1487, dpm: 0x0d2a, gy: 2064, gm: 4, gd: 18 },
+  { hy: 1488, dpm: 0x0a56, gy: 2065, gm: 4, gd: 7 },
+  { hy: 1489, dpm: 0x04ae, gy: 2066, gm: 3, gd: 27 },
+  { hy: 1490, dpm: 0x096d, gy: 2067, gm: 3, gd: 16 },
+  { hy: 1491, dpm: 0x0d6a, gy: 2068, gm: 3, gd: 5 },
+  { hy: 1492, dpm: 0x0b54, gy: 2069, gm: 2, gd: 23 },
+  { hy: 1493, dpm: 0x0b29, gy: 2070, gm: 2, gd: 12 },
+  { hy: 1494, dpm: 0x0a93, gy: 2071, gm: 2, gd: 1 },
+  { hy: 1495, dpm: 0x052b, gy: 2072, gm: 1, gd: 21 },
+  { hy: 1496, dpm: 0x0a57, gy: 2073, gm: 1, gd: 9 },
  { hy: 1497, dpm: 0x0536, gy: 2073, gm: 12, gd: 30 },
-  { hy: 1498, dpm: 0x0AB5, gy: 2074, gm: 12, gd: 19 },
-  { hy: 1499, dpm: 0x06AA, gy: 2075, gm: 12, gd:  9 },
-  { hy: 1500, dpm: 0x0E93, gy: 2076, gm: 11, gd: 27 },
-  { hy: 1501, dpm:      0, gy: 2077, gm: 11, gd: 17 },
+  { hy: 1498, dpm: 0x0ab5, gy: 2074, gm: 12, gd: 19 },
+  { hy: 1499, dpm: 0x06aa, gy: 2075, gm: 12, gd: 9 },
+  { hy: 1500, dpm: 0x0e93, gy: 2076, gm: 11, gd: 27 },
+  { hy: 1501, dpm: 0, gy: 2077, gm: 11, gd: 17 },
 ];
--- a/src/engines/fcna.ts
+++ b/src/engines/fcna.ts
@ -8,15 +8,15 @@
 // Chapter 49, accurate to within a few minutes for 1000-3000 CE.

 import { hDatesTable } from '../data/hDates';
+import { MS_PER_DAY, MONTHS_PER_YEAR } from '../constants';
 import type { CalendarEngine, HijriDate } from '../types';

 // ─── Constants ───────────────────────────────────────────────────────────────

-const SYNODIC    = 29.530588861;  // Mean synodic month (days)
-const JDE0       = 2451550.09766; // Meeus k=0 (2nd ed. Ch.49: 2451550.09765; 0.864 s diff, within tolerance)
-const JDE_UNIX   = 2440587.5;     // JDE of Unix epoch 1970-01-01 00:00 UTC
-const MS_PER_DAY = 86_400_000;
-const TO_RAD     = Math.PI / 180;
+const SYNODIC = 29.530588861; // Mean synodic month (days)
+const JDE0 = 2451550.09766; // Meeus k=0 (2nd ed. Ch.49: 2451550.09765; 0.864 s diff, within tolerance)
+const JDE_UNIX = 2440587.5; // JDE of Unix epoch 1970-01-01 00:00 UTC
+const TO_RAD = Math.PI / 180;

 // Approximate k index of 1 Muharram 1 AH in Meeus numbering.
 // Islamic epoch JDE ~1948438.5 -> k ~= (1948438.5 - JDE0) / SYNODIC ~= -17037.
@ -25,104 +25,88 @@ const K_EPOCH = -17037;
 // ─── Meeus Chapter 49: corrected new moon JDE ────────────────────────────────

 function newMoonJDE(k: number): number {
-  const T  = k / 1236.85;
+  const T = k / 1236.85;
  const T2 = T * T;
  const T3 = T2 * T;
  const T4 = T3 * T;

-  let jde = JDE0
-    + SYNODIC * k
-    + 0.00015437 * T2
-    - 0.000000150 * T3
-    + 0.00000000073 * T4;
+  let jde = JDE0 + SYNODIC * k + 0.00015437 * T2 - 0.00000015 * T3 + 0.00000000073 * T4;

-  const M = (2.5534
-    + 29.10535670 * k
-    - 0.0000014 * T2
-    - 0.00000011 * T3) % 360;
+  const M = (2.5534 + 29.1053567 * k - 0.0000014 * T2 - 0.00000011 * T3) % 360;

-  const Mprime = (201.5643
-    + 385.81693528 * k
-    + 0.0107582 * T2
-    + 0.00001238 * T3
-    - 0.000000058 * T4) % 360;
+  const Mprime =
+    (201.5643 + 385.81693528 * k + 0.0107582 * T2 + 0.00001238 * T3 - 0.000000058 * T4) % 360;

-  const F = (160.7108
-    + 390.67050284 * k
-    - 0.0016118 * T2
-    - 0.00000227 * T3
-    + 0.000000011 * T4) % 360;
+  const F =
+    (160.7108 + 390.67050284 * k - 0.0016118 * T2 - 0.00000227 * T3 + 0.000000011 * T4) % 360;

-  const Omega = (124.7746
-    - 1.56375588 * k
-    + 0.0020672 * T2
-    + 0.00000215 * T3) % 360;
+  const Omega = (124.7746 - 1.56375588 * k + 0.0020672 * T2 + 0.00000215 * T3) % 360;

-  const E  = 1 - 0.002516 * T - 0.0000074 * T2;
+  const E = 1 - 0.002516 * T - 0.0000074 * T2;
  const E2 = E * E;

-  const Mrad  = M * TO_RAD;
+  const Mrad = M * TO_RAD;
  const Mprad = Mprime * TO_RAD;
-  const Frad  = F * TO_RAD;
-  const Orad  = Omega * TO_RAD;
+  const Frad = F * TO_RAD;
+  const Orad = Omega * TO_RAD;

  jde +=
-    - 0.40720 * Math.sin(Mprad)
-    + 0.17241 * E  * Math.sin(Mrad)
-    + 0.01608 * Math.sin(2 * Mprad)
-    + 0.01039 * Math.sin(2 * Frad)
-    + 0.00739 * E  * Math.sin(Mprad - Mrad)
-    - 0.00514 * E  * Math.sin(Mprad + Mrad)
-    + 0.00208 * E2 * Math.sin(2 * Mrad)
-    - 0.00111 * Math.sin(Mprad - 2 * Frad)
-    - 0.00057 * Math.sin(Mprad + 2 * Frad)
-    + 0.00056 * E  * Math.sin(2 * Mprad + Mrad)
-    - 0.00042 * Math.sin(3 * Mprad)
-    + 0.00042 * E  * Math.sin(Mrad + 2 * Frad)
-    + 0.00038 * E  * Math.sin(Mrad - 2 * Frad)
-    - 0.00024 * E  * Math.sin(2 * Mprad - Mrad)
-    - 0.00017 * Math.sin(Orad)
-    - 0.00007 * Math.sin(Mprad + 2 * Mrad)
-    + 0.00004 * Math.sin(2 * Mprad - 2 * Frad)
-    + 0.00004 * Math.sin(3 * Mrad)
-    + 0.00003 * Math.sin(Mprad + Mrad - 2 * Frad)
-    + 0.00003 * Math.sin(2 * Mprad + 2 * Frad)
-    - 0.00003 * Math.sin(Mprad + Mrad + 2 * Frad)
-    + 0.00003 * Math.sin(Mprad - Mrad + 2 * Frad)
-    - 0.00002 * Math.sin(Mprad - Mrad - 2 * Frad)
-    - 0.00002 * Math.sin(3 * Mprad + Mrad)
-    + 0.00002 * Math.sin(4 * Mprad);
+    -0.4072 * Math.sin(Mprad) +
+    0.17241 * E * Math.sin(Mrad) +
+    0.01608 * Math.sin(2 * Mprad) +
+    0.01039 * Math.sin(2 * Frad) +
+    0.00739 * E * Math.sin(Mprad - Mrad) -
+    0.00514 * E * Math.sin(Mprad + Mrad) +
+    0.00208 * E2 * Math.sin(2 * Mrad) -
+    0.00111 * Math.sin(Mprad - 2 * Frad) -
+    0.00057 * Math.sin(Mprad + 2 * Frad) +
+    0.00056 * E * Math.sin(2 * Mprad + Mrad) -
+    0.00042 * Math.sin(3 * Mprad) +
+    0.00042 * E * Math.sin(Mrad + 2 * Frad) +
+    0.00038 * E * Math.sin(Mrad - 2 * Frad) -
+    0.00024 * E * Math.sin(2 * Mprad - Mrad) -
+    0.00017 * Math.sin(Orad) -
+    0.00007 * Math.sin(Mprad + 2 * Mrad) +
+    0.00004 * Math.sin(2 * Mprad - 2 * Frad) +
+    0.00004 * Math.sin(3 * Mrad) +
+    0.00003 * Math.sin(Mprad + Mrad - 2 * Frad) +
+    0.00003 * Math.sin(2 * Mprad + 2 * Frad) -
+    0.00003 * Math.sin(Mprad + Mrad + 2 * Frad) +
+    0.00003 * Math.sin(Mprad - Mrad + 2 * Frad) -
+    0.00002 * Math.sin(Mprad - Mrad - 2 * Frad) -
+    0.00002 * Math.sin(3 * Mprad + Mrad) +
+    0.00002 * Math.sin(4 * Mprad);

-  const A1  = (299.77 +  0.107408 * k - 0.009173 * T2) * TO_RAD;
-  const A2  = (251.88 +  0.016321 * k) * TO_RAD;
-  const A3  = (251.83 + 26.651886 * k) * TO_RAD;
-  const A4  = (349.42 + 36.412478 * k) * TO_RAD;
-  const A5  = ( 84.66 + 18.206239 * k) * TO_RAD;
-  const A6  = (141.74 + 53.303771 * k) * TO_RAD;
-  const A7  = (207.14 +  2.453732 * k) * TO_RAD;
-  const A8  = (154.84 +  7.306860 * k) * TO_RAD;
-  const A9  = ( 34.52 + 27.261239 * k) * TO_RAD;
-  const A10 = (207.19 +  0.121824 * k) * TO_RAD;
-  const A11 = (291.34 +  1.844379 * k) * TO_RAD;
+  const A1 = (299.77 + 0.107408 * k - 0.009173 * T2) * TO_RAD;
+  const A2 = (251.88 + 0.016321 * k) * TO_RAD;
+  const A3 = (251.83 + 26.651886 * k) * TO_RAD;
+  const A4 = (349.42 + 36.412478 * k) * TO_RAD;
+  const A5 = (84.66 + 18.206239 * k) * TO_RAD;
+  const A6 = (141.74 + 53.303771 * k) * TO_RAD;
+  const A7 = (207.14 + 2.453732 * k) * TO_RAD;
+  const A8 = (154.84 + 7.30686 * k) * TO_RAD;
+  const A9 = (34.52 + 27.261239 * k) * TO_RAD;
+  const A10 = (207.19 + 0.121824 * k) * TO_RAD;
+  const A11 = (291.34 + 1.844379 * k) * TO_RAD;
  const A12 = (161.72 + 24.198154 * k) * TO_RAD;
  const A13 = (239.56 + 25.513099 * k) * TO_RAD;
-  const A14 = (331.55 +  3.592518 * k) * TO_RAD;
+  const A14 = (331.55 + 3.592518 * k) * TO_RAD;

  jde +=
-    + 0.000325 * Math.sin(A1)
-    + 0.000165 * Math.sin(A2)
-    + 0.000164 * Math.sin(A3)
-    + 0.000126 * Math.sin(A4)
-    + 0.000110 * Math.sin(A5)
-    + 0.000062 * Math.sin(A6)
-    + 0.000060 * Math.sin(A7)
-    + 0.000056 * Math.sin(A8)
-    + 0.000047 * Math.sin(A9)
-    + 0.000042 * Math.sin(A10)
-    + 0.000040 * Math.sin(A11)
-    + 0.000037 * Math.sin(A12)
-    + 0.000035 * Math.sin(A13)
-    + 0.000023 * Math.sin(A14);
+    +0.000325 * Math.sin(A1) +
+    0.000165 * Math.sin(A2) +
+    0.000164 * Math.sin(A3) +
+    0.000126 * Math.sin(A4) +
+    0.00011 * Math.sin(A5) +
+    0.000062 * Math.sin(A6) +
+    0.00006 * Math.sin(A7) +
+    0.000056 * Math.sin(A8) +
+    0.000047 * Math.sin(A9) +
+    0.000042 * Math.sin(A10) +
+    0.00004 * Math.sin(A11) +
+    0.000037 * Math.sin(A12) +
+    0.000035 * Math.sin(A13) +
+    0.000023 * Math.sin(A14);

  return jde;
 }
@ -143,15 +127,15 @@ function utcMsToKApprox(ms: number): number {
 // Searches k0-2 through k0+2 to handle any estimation error.
 function nearestNewMoonMs(anchorMs: number): number {
  const k0 = Math.round(utcMsToKApprox(anchorMs));
-  let bestMs   = 0;
+  let bestMs = 0;
  let bestDist = Infinity;

  for (let k = k0 - 2; k <= k0 + 2; k++) {
-    const ms   = jdeToUtcMs(newMoonJDE(k));
+    const ms = jdeToUtcMs(newMoonJDE(k));
    const dist = Math.abs(ms - anchorMs);
    if (dist < bestDist) {
      bestDist = dist;
-      bestMs   = ms;
+      bestMs = ms;
    }
  }

@ -163,7 +147,7 @@ function nearestNewMoonMs(anchorMs: number): number {
 // Returns the midnight UTC ms that starts the new FCNA Hijri month.
 function fcnaCriterionMs(conjMs: number): number {
  const midnight = Math.floor(conjMs / MS_PER_DAY) * MS_PER_DAY;
-  const noon     = midnight + 12 * 3_600_000;
+  const noon = midnight + 12 * 3_600_000;
  return conjMs < noon ? midnight + MS_PER_DAY : midnight + 2 * MS_PER_DAY;
 }

@ -173,13 +157,17 @@ function fcnaCriterionMs(conjMs: number): number {
 // In-range years (1318-1500 H): binary-search table, sum dpm day counts.
 // Out-of-range years: estimate from Islamic epoch + mean synodic month count.
 function uaqAnchorMs(hy: number, hm: number): number {
-  let lo = 0, hi = hDatesTable.length - 1, found = -1;
+  let lo = 0,
+    hi = hDatesTable.length - 1,
+    found = -1;
  while (lo <= hi) {
    const mid = (lo + hi) >>> 1;
    const midHy = hDatesTable[mid].hy;
-    if (midHy === hy)     { found = mid; break; }
-    else if (midHy < hy)  lo = mid + 1;
-    else                   hi = mid - 1;
+    if (midHy === hy) {
+      found = mid;
+      break;
+    } else if (midHy < hy) lo = mid + 1;
+    else hi = mid - 1;
  }

  if (found !== -1 && hDatesTable[found].dpm !== 0) {
@ -191,7 +179,7 @@ function uaqAnchorMs(hy: number, hm: number): number {
    return Date.UTC(r.gy, r.gm - 1, r.gd) + days * MS_PER_DAY;
  }

-  const monthsFromEpoch = (hy - 1) * 12 + (hm - 1);
+  const monthsFromEpoch = (hy - 1) * MONTHS_PER_YEAR + (hm - 1);
  const kApprox = K_EPOCH + monthsFromEpoch;
  return jdeToUtcMs(newMoonJDE(kApprox));
 }
@ -207,9 +195,12 @@ function fcnaMonthStartMs(hy: number, hm: number): number {
 // ─── FCNA month length ───────────────────────────────────────────────────────

 function fcnaDaysInMonth(hy: number, hm: number): number {
+  if (hm < 1 || hm > MONTHS_PER_YEAR) {
+    throw new RangeError(`month must be 1-12, got ${hm}`);
+  }
  const thisStart = fcnaMonthStartMs(hy, hm);
-  const nextHy    = hm < 12 ? hy : hy + 1;
-  const nextHm    = hm < 12 ? hm + 1 : 1;
+  const nextHy = hm < MONTHS_PER_YEAR ? hy : hy + 1;
+  const nextHm = hm < MONTHS_PER_YEAR ? hm + 1 : 1;
  const nextStart = fcnaMonthStartMs(nextHy, nextHm);
  return Math.round((nextStart - thisStart) / MS_PER_DAY);
 }
@ -229,22 +220,25 @@ function fcnaToHijri(gregorianDate: Date): HijriDate | null {
  );

  const kApprox = utcMsToKApprox(inputMs - 15 * MS_PER_DAY);
-  const k0      = Math.floor(kApprox);
+  const k0 = Math.floor(kApprox);

  for (let ki = k0 - 1; ki <= k0 + 1; ki++) {
-    const conjMs      = jdeToUtcMs(newMoonJDE(ki));
-    const monthStart  = fcnaCriterionMs(conjMs);
+    const conjMs = jdeToUtcMs(newMoonJDE(ki));
+    const monthStart = fcnaCriterionMs(conjMs);

    if (monthStart > inputMs) continue;

-    const nextConjMs     = jdeToUtcMs(newMoonJDE(ki + 1));
+    const nextConjMs = jdeToUtcMs(newMoonJDE(ki + 1));
    const nextMonthStart = fcnaCriterionMs(nextConjMs);

    if (inputMs < nextMonthStart) {
      const monthsFromEpoch = ki - K_EPOCH;
-      let hy = Math.floor(monthsFromEpoch / 12) + 1;
-      let hm = (monthsFromEpoch % 12) + 1;
-      if (hm <= 0) { hm += 12; hy--; }
+      let hy = Math.floor(monthsFromEpoch / MONTHS_PER_YEAR) + 1;
+      let hm = (monthsFromEpoch % MONTHS_PER_YEAR) + 1;
+      if (hm <= 0) {
+        hm += MONTHS_PER_YEAR;
+        hy--;
+      }
      if (hy < 1) return null;

      const hd = Math.round((inputMs - monthStart) / MS_PER_DAY) + 1;
@ -258,7 +252,7 @@ function fcnaToHijri(gregorianDate: Date): HijriDate | null {
 // ─── FCNA Hijri -> Gregorian ──────────────────────────────────────────────────

 function fcnaToGregorian(hy: number, hm: number, hd: number): Date | null {
-  if (hy < 1 || hm < 1 || hm > 12 || hd < 1) return null;
+  if (hy < 1 || hm < 1 || hm > MONTHS_PER_YEAR || hd < 1) return null;
  const days = fcnaDaysInMonth(hy, hm);
  if (hd > days) return null;
  const startMs = fcnaMonthStartMs(hy, hm);
@ -268,7 +262,7 @@ function fcnaToGregorian(hy: number, hm: number, hd: number): Date | null {
 // ─── FCNA validation ─────────────────────────────────────────────────────────

 function fcnaIsValid(hy: number, hm: number, hd: number): boolean {
-  if (hy < 1 || hm < 1 || hm > 12 || hd < 1) return false;
+  if (hy < 1 || hm < 1 || hm > MONTHS_PER_YEAR || hd < 1) return false;
  return hd <= fcnaDaysInMonth(hy, hm);
 }

@ -276,8 +270,8 @@ function fcnaIsValid(hy: number, hm: number, hd: number): boolean {

 export const fcnaEngine: CalendarEngine = {
  id: 'fcna',
-  toHijri:     fcnaToHijri,
+  toHijri: fcnaToHijri,
  toGregorian: fcnaToGregorian,
-  isValid:     fcnaIsValid,
+  isValid: fcnaIsValid,
  daysInMonth: fcnaDaysInMonth,
 };
--- a/src/engines/uaq.ts
+++ b/src/engines/uaq.ts
@ -5,7 +5,32 @@
 // a 12-bit days-per-month bitmask. Dates outside that window return null.

 import { hDatesTable } from '../data/hDates';
-import type { CalendarEngine, HijriDate } from '../types';
+import { MS_PER_DAY, MONTHS_PER_YEAR } from '../constants';
+import type { CalendarEngine, HijriDate, HijriYearRecord } from '../types';
+
+/**
+ * Binary search for a Hijri year entry in the UAQ table.
+ *
+ * Returns the entry whose `hy` matches exactly, or null if the year is not
+ * present in the table. The table covers Hijri years 1318 through 1501
+ * (the final entry is a sentinel with dpm === 0).
+ *
+ * @param hy - Hijri year to locate
+ * @returns the matching table entry, or null if not found
+ */
+function findYearEntry(hy: number): HijriYearRecord | null {
+  let lo = 0;
+  let hi = hDatesTable.length - 1;
+
+  while (lo <= hi) {
+    const mid = (lo + hi) >>> 1;
+    const midHy = hDatesTable[mid].hy;
+    if (midHy === hy) return hDatesTable[mid];
+    else if (midHy < hy) lo = mid + 1;
+    else hi = mid - 1;
+  }
+  return null;
+}

 // toHijri uses local date components (getFullYear, getMonth, getDate) so that
 // the calendar-date lookup is timezone-safe regardless of the host environment.
@ -14,11 +39,7 @@ function uaqToHijri(date: Date): HijriDate | null {
    throw new Error('Invalid Gregorian date');
  }

-  const inputUtc = Date.UTC(
-    date.getFullYear(),
-    date.getMonth(),
-    date.getDate(),
-  );
+  const inputUtc = Date.UTC(date.getFullYear(), date.getMonth(), date.getDate());

  // Binary search: find the last table entry whose Gregorian start date <= input.
  let lo = 0;
@ -43,10 +64,10 @@ function uaqToHijri(date: Date): HijriDate | null {

  const record = hDatesTable[found];
  const startUtc = Date.UTC(record.gy, record.gm - 1, record.gd);
-  let remaining = Math.round((inputUtc - startUtc) / 86_400_000);
+  let remaining = Math.round((inputUtc - startUtc) / MS_PER_DAY);
  let hijriMonth = 0;

-  for (let i = 0; i < 12; i++) {
+  for (let i = 0; i < MONTHS_PER_YEAR; i++) {
    const dim = (record.dpm >> i) & 1 ? 30 : 29;
    if (remaining < dim) {
      hijriMonth = i + 1;
@ -65,22 +86,9 @@ function uaqToGregorian(hy: number, hm: number, hd: number): Date | null {
    return null;
  }

-  // Binary search on hy.
-  let lo = 0;
-  let hi = hDatesTable.length - 1;
-  let found = -1;
+  const record = findYearEntry(hy);
+  if (!record) return null;

-  while (lo <= hi) {
-    const mid = (lo + hi) >>> 1;
-    const midHy = hDatesTable[mid].hy;
-    if (midHy === hy)     { found = mid; break; }
-    else if (midHy < hy)  lo = mid + 1;
-    else                   hi = mid - 1;
-  }
-
-  if (found === -1) return null;
-
-  const record = hDatesTable[found];
  let totalDays = 0;

  for (let i = 0; i < hm - 1; i++) {
@ -88,53 +96,35 @@ function uaqToGregorian(hy: number, hm: number, hd: number): Date | null {
  }
  totalDays += hd - 1;

-  return new Date(Date.UTC(record.gy, record.gm - 1, record.gd) + totalDays * 86_400_000);
+  return new Date(Date.UTC(record.gy, record.gm - 1, record.gd) + totalDays * MS_PER_DAY);
 }

 function uaqIsValid(hy: number, hm: number, hd: number): boolean {
-  if (hm < 1 || hm > 12 || hd < 1) return false;
+  if (hm < 1 || hm > MONTHS_PER_YEAR || hd < 1) return false;

-  let lo = 0;
-  let hi = hDatesTable.length - 1;
-  let found = -1;
+  const record = findYearEntry(hy);
+  if (!record || record.dpm === 0) return false;

-  while (lo <= hi) {
-    const mid = (lo + hi) >>> 1;
-    const midHy = hDatesTable[mid].hy;
-    if (midHy === hy)     { found = mid; break; }
-    else if (midHy < hy)  lo = mid + 1;
-    else                   hi = mid - 1;
-  }
-
-  if (found === -1 || hDatesTable[found].dpm === 0) return false;
-
-  const dim = (hDatesTable[found].dpm >> (hm - 1)) & 1 ? 30 : 29;
+  const dim = (record.dpm >> (hm - 1)) & 1 ? 30 : 29;
  return hd <= dim;
 }

 function uaqDaysInMonth(hy: number, hm: number): number {
-  let lo = 0;
-  let hi = hDatesTable.length - 1;
-  let found = -1;
-
-  while (lo <= hi) {
-    const mid = (lo + hi) >>> 1;
-    const midHy = hDatesTable[mid].hy;
-    if (midHy === hy)     { found = mid; break; }
-    else if (midHy < hy)  lo = mid + 1;
-    else                   hi = mid - 1;
+  if (hm < 1 || hm > MONTHS_PER_YEAR) {
+    throw new RangeError(`month must be 1-12, got ${hm}`);
  }

-  if (found === -1 || hDatesTable[found].dpm === 0) {
+  const record = findYearEntry(hy);
+  if (!record || record.dpm === 0) {
    throw new RangeError(`Hijri year ${hy} is outside the UAQ table range (1318-1500).`);
  }
-  return (hDatesTable[found].dpm >> (hm - 1)) & 1 ? 30 : 29;
+  return (record.dpm >> (hm - 1)) & 1 ? 30 : 29;
 }

 export const uaqEngine: CalendarEngine = {
  id: 'uaq',
-  toHijri:    uaqToHijri,
+  toHijri: uaqToHijri,
  toGregorian: uaqToGregorian,
-  isValid:    uaqIsValid,
+  isValid: uaqIsValid,
  daysInMonth: uaqDaysInMonth,
 };
--- a/src/index.ts
+++ b/src/index.ts
@ -1,4 +1,6 @@
-// Register built-in engines at module load.
+// Built-in engines are registered at module load so that 'uaq' and 'fcna' are
+// available immediately on import. This module-level side effect is intentional
+// and documented in the sideEffects field of package.json.
 import { uaqEngine } from './engines/uaq';
 import { fcnaEngine } from './engines/fcna';
 import { registerCalendar } from './registry';
@ -9,6 +11,9 @@ registerCalendar('fcna', fcnaEngine);
 // Registry
 export { registerCalendar, getCalendar, listCalendars } from './registry';

+// Constants
+export { MS_PER_DAY, MONTHS_PER_YEAR } from './constants';
+
 // Types
 export type { HijriDate, HijriYearRecord, CalendarEngine, ConversionOptions } from './types';

@ -23,6 +28,17 @@ export { hwLong, hwShort, hwNumeric } from './names/weekdays';
 import { getCalendar } from './registry';
 import type { HijriDate, ConversionOptions } from './types';

+/**
+ * Convert a Gregorian date to a Hijri date.
+ *
+ * Uses the UAQ (Umm al-Qura) calendar by default. Pass `{ calendar: 'fcna' }`
+ * or any registered calendar name via options to use a different engine.
+ *
+ * @param date - a valid JavaScript Date object
+ * @param options - conversion options (calendar engine selection)
+ * @returns the corresponding Hijri date, or null if the date is out of range
+ * @throws {Error} if `date` is not a valid Date instance
+ */
 export function toHijri(date: Date, options?: ConversionOptions): HijriDate | null {
  if (!(date instanceof Date) || isNaN(date.getTime())) {
    throw new Error('Invalid Gregorian date');
@ -30,6 +46,17 @@ export function toHijri(date: Date, options?: ConversionOptions): HijriDate | nu
  return getCalendar(options?.calendar ?? 'uaq').toHijri(date);
 }

+/**
+ * Convert a Hijri date to a Gregorian date.
+ *
+ * Uses the UAQ calendar by default.
+ *
+ * @param hy - Hijri year
+ * @param hm - Hijri month (1-12)
+ * @param hd - Hijri day (1-30)
+ * @param options - conversion options (calendar engine selection)
+ * @returns a Date in UTC, or null if the input is invalid or out of range
+ */
 export function toGregorian(
  hy: number,
  hm: number,
@ -39,6 +66,15 @@ export function toGregorian(
  return getCalendar(options?.calendar ?? 'uaq').toGregorian(hy, hm, hd);
 }

+/**
+ * Check whether a Hijri date is valid for the given calendar engine.
+ *
+ * @param hy - Hijri year
+ * @param hm - Hijri month (1-12)
+ * @param hd - Hijri day (1-30)
+ * @param options - conversion options (calendar engine selection)
+ * @returns true if the date is valid
+ */
 export function isValidHijriDate(
  hy: number,
  hm: number,
@ -48,10 +84,15 @@ export function isValidHijriDate(
  return getCalendar(options?.calendar ?? 'uaq').isValid(hy, hm, hd);
 }

-export function daysInHijriMonth(
-  hy: number,
-  hm: number,
-  options?: ConversionOptions,
-): number {
+/**
+ * Return the number of days in a given Hijri month.
+ *
+ * @param hy - Hijri year
+ * @param hm - Hijri month (1-12)
+ * @param options - conversion options (calendar engine selection)
+ * @returns 29 or 30
+ * @throws {RangeError} if the month or year is out of range
+ */
+export function daysInHijriMonth(hy: number, hm: number, options?: ConversionOptions): number {
  return getCalendar(options?.calendar ?? 'uaq').daysInMonth(hy, hm);
 }
--- a/src/names/months.ts
+++ b/src/names/months.ts
@ -2,46 +2,46 @@
 // Index 0 = Muharram (month 1), index 11 = Dhul Hijjah (month 12).

 export const hmLong = [
-  "Muharram",       // 1
-  "Safar",          // 2
-  "Rabi'l Awwal",   // 3
-  "Rabi'l Thani",   // 4
-  "Jumadal Awwal",  // 5
-  "Jumadal Thani",  // 6
-  "Rajab",          // 7
-  "Sha'ban",        // 8
-  "Ramadan",        // 9
-  "Shawwal",        // 10
-  "Dhul Qi'dah",    // 11
-  "Dhul Hijjah",    // 12
+  'Muharram', // 1
+  'Safar', // 2
+  "Rabi'l Awwal", // 3
+  "Rabi'l Thani", // 4
+  'Jumadal Awwal', // 5
+  'Jumadal Thani', // 6
+  'Rajab', // 7
+  "Sha'ban", // 8
+  'Ramadan', // 9
+  'Shawwal', // 10
+  "Dhul Qi'dah", // 11
+  'Dhul Hijjah', // 12
 ];

 export const hmMedium = [
-  "Muharram",
-  "Safar",
-  "Rabi1",
-  "Rabi2",
-  "Jumada1",
-  "Jumada2",
-  "Rajab",
-  "Shaban",
-  "Ramadan",
-  "Shawwal",
-  "Dhul-Qidah",
-  "Dhul-Hijjah",
+  'Muharram',
+  'Safar',
+  'Rabi1',
+  'Rabi2',
+  'Jumada1',
+  'Jumada2',
+  'Rajab',
+  'Shaban',
+  'Ramadan',
+  'Shawwal',
+  'Dhul-Qidah',
+  'Dhul-Hijjah',
 ];

 export const hmShort = [
-  "Muh",
-  "Saf",
-  "Ra1",
-  "Ra2",
-  "Ju1",
-  "Ju2",
-  "Raj",
-  "Shb",
-  "Ram",
-  "Shw",
-  "DhQ",
-  "DhH",
+  'Muh',
+  'Saf',
+  'Ra1',
+  'Ra2',
+  'Ju1',
+  'Ju2',
+  'Raj',
+  'Shb',
+  'Ram',
+  'Shw',
+  'DhQ',
+  'DhH',
 ];
--- a/src/names/weekdays.ts
+++ b/src/names/weekdays.ts
@ -2,23 +2,23 @@
 // Index 0 = Sunday, index 6 = Saturday (matching JS Date.getDay()).

 export const hwLong = [
-  "Yawm al-Ahad",        // Sunday
-  "Yawm al-Ithnayn",     // Monday
-  "Yawm ath-Thulatha'",  // Tuesday
-  "Yawm al-Arba`a'",     // Wednesday
-  "Yawm al-Khamis",      // Thursday
-  "Yawm al-Jum`a",       // Friday
-  "Yawm as-Sabt",        // Saturday
+  'Yawm al-Ahad', // Sunday
+  'Yawm al-Ithnayn', // Monday
+  "Yawm ath-Thulatha'", // Tuesday
+  "Yawm al-Arba`a'", // Wednesday
+  'Yawm al-Khamis', // Thursday
+  'Yawm al-Jum`a', // Friday
+  'Yawm as-Sabt', // Saturday
 ];

 export const hwShort = [
-  "Ahad",   // Sunday
-  "Ithn",   // Monday
-  "Thul",   // Tuesday
-  "Arba",   // Wednesday
-  "Kham",   // Thursday
-  "Jum`a",  // Friday
-  "Sabt",   // Saturday
+  'Ahad', // Sunday
+  'Ithn', // Monday
+  'Thul', // Tuesday
+  'Arba', // Wednesday
+  'Kham', // Thursday
+  'Jum`a', // Friday
+  'Sabt', // Saturday
 ];

 // Numeric representation: 1 = Sunday, 7 = Saturday.
--- a/src/registry.ts
+++ b/src/registry.ts
@ -2,21 +2,42 @@ import type { CalendarEngine } from './types';

 const _engines = new Map<string, CalendarEngine>();

+/**
+ * Register a calendar engine under the given name.
+ *
+ * Once registered, the engine can be selected via `{ calendar: name }` in any
+ * conversion function or retrieved directly with {@link getCalendar}.
+ *
+ * @param name - unique identifier for the calendar (e.g. 'uaq', 'fcna')
+ * @param engine - an object implementing the {@link CalendarEngine} interface
+ */
 export function registerCalendar(name: string, engine: CalendarEngine): void {
  _engines.set(name, engine);
 }

+/**
+ * Retrieve a registered calendar engine by name.
+ *
+ * @param name - the calendar identifier passed to {@link registerCalendar}
+ * @returns the matching engine
+ * @throws {Error} if no engine is registered under that name
+ */
 export function getCalendar(name: string): CalendarEngine {
  const engine = _engines.get(name);
  if (!engine) {
    const available = listCalendars().join(', ');
    throw new Error(
-      `Unknown Hijri calendar: "${name}". Available: ${available}. Register custom calendars with registerCalendar().`
+      `Unknown Hijri calendar: "${name}". Available: ${available}. Register custom calendars with registerCalendar().`,
    );
  }
  return engine;
 }

+/**
+ * List the names of all registered calendar engines.
+ *
+ * @returns an array of calendar names (e.g. ['uaq', 'fcna'])
+ */
 export function listCalendars(): string[] {
  return Array.from(_engines.keys());
 }
--- a/src/types.ts
+++ b/src/types.ts
@ -5,11 +5,11 @@ export interface HijriDate {
 }

 export interface HijriYearRecord {
-  hy:  number; // Hijri year
+  hy: number; // Hijri year
  dpm: number; // days-per-month bitmask (bit 0 = month 1: 1 -> 30 days, 0 -> 29 days)
-  gy:  number; // Gregorian year of 1 Muharram
-  gm:  number; // Gregorian month of 1 Muharram (1-based)
-  gd:  number; // Gregorian day of 1 Muharram
+  gy: number; // Gregorian year of 1 Muharram
+  gm: number; // Gregorian month of 1 Muharram (1-based)
+  gd: number; // Gregorian day of 1 Muharram
 }

 // Any calendar engine must implement this interface.
--- a/test-cjs.cjs
+++ b/test-cjs.cjs
@ -1,8 +1,9 @@
 'use strict';

 // CJS test suite for hijri-core.
-// Subset of test.mjs — verifies the CommonJS build works correctly.
+// Subset of test.mjs to verify the CommonJS build works correctly.

+const { describe, it } = require('node:test');
 const assert = require('node:assert/strict');
 const {
  toHijri,
@ -19,126 +20,131 @@ const {
  hwNumeric,
 } = require('./dist/index.cjs');

-let passed = 0;
-let failed = 0;
+// ─── Exports ────────────────────────────────────────────────────────────────

-function test(name, fn) {
-  try {
-    fn();
-    console.log(`[${name}]... PASS`);
-    passed++;
-  } catch (err) {
-    console.error(`[${name}]... FAIL: ${err.message}`);
-    failed++;
-  }
-}
-
-// Exports
-test('CJS exports: toHijri is a function', () => {
-  assert.equal(typeof toHijri, 'function');
-});
-test('CJS exports: toGregorian is a function', () => {
-  assert.equal(typeof toGregorian, 'function');
-});
-test('CJS exports: hDatesTable is an array', () => {
-  assert.ok(Array.isArray(hDatesTable));
-  assert.ok(hDatesTable.length > 180);
-});
-test('CJS exports: hmLong[8] = Ramadan', () => {
-  assert.equal(hmLong[8], 'Ramadan');
-});
-test('CJS exports: hmShort[8] = Ram', () => {
-  assert.equal(hmShort[8], 'Ram');
-});
-test('CJS exports: hwLong[4] = Yawm al-Khamis', () => {
-  assert.equal(hwLong[4], 'Yawm al-Khamis');
-});
-test('CJS exports: hwNumeric[0] = 1', () => {
-  assert.equal(hwNumeric[0], 1);
+describe('CJS exports', () => {
+  it('toHijri is a function', () => {
+    assert.equal(typeof toHijri, 'function');
+  });
+  it('toGregorian is a function', () => {
+    assert.equal(typeof toGregorian, 'function');
+  });
+  it('hDatesTable is an array with > 180 entries', () => {
+    assert.ok(Array.isArray(hDatesTable));
+    assert.ok(hDatesTable.length > 180);
+  });
+  it('hmLong[8] = Ramadan', () => {
+    assert.equal(hmLong[8], 'Ramadan');
+  });
+  it('hmShort[8] = Ram', () => {
+    assert.equal(hmShort[8], 'Ram');
+  });
+  it('hwLong[4] = Yawm al-Khamis', () => {
+    assert.equal(hwLong[4], 'Yawm al-Khamis');
+  });
+  it('hwNumeric[0] = 1', () => {
+    assert.equal(hwNumeric[0], 1);
+  });
 });

-// UAQ conversions
-test('CJS UAQ toGregorian: 1444/9/1 = 2023-03-23', () => {
-  const d = toGregorian(1444, 9, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2023-03-23');
-});
-test('CJS UAQ toGregorian: 1446/9/1 = 2025-03-01', () => {
-  const d = toGregorian(1446, 9, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
-});
-test('CJS UAQ toHijri: 2023-03-23 = 1444/9/1', () => {
-  const h = toHijri(new Date(2023, 2, 23, 12));
-  assert.ok(h !== null);
-  assert.equal(h.hy, 1444);
-  assert.equal(h.hm, 9);
-  assert.equal(h.hd, 1);
-});
-test('CJS UAQ isValid: 1444/9/1 = true', () => {
-  assert.equal(isValidHijriDate(1444, 9, 1), true);
-});
-test('CJS UAQ isValid: 1317/1/1 = false', () => {
-  assert.equal(isValidHijriDate(1317, 1, 1), false);
-});
-test('CJS UAQ daysInMonth: Ramadan 1444 = 29', () => {
-  assert.equal(daysInHijriMonth(1444, 9), 29);
+// ─── UAQ conversions ────────────────────────────────────────────────────────
+
+describe('CJS UAQ conversions', () => {
+  it('toGregorian: 1444/9/1 = 2023-03-23', () => {
+    const d = toGregorian(1444, 9, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2023-03-23');
+  });
+  it('toGregorian: 1446/9/1 = 2025-03-01', () => {
+    const d = toGregorian(1446, 9, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
+  });
+  it('toHijri: 2023-03-23 = 1444/9/1', () => {
+    const h = toHijri(new Date(2023, 2, 23, 12));
+    assert.ok(h !== null);
+    assert.equal(h.hy, 1444);
+    assert.equal(h.hm, 9);
+    assert.equal(h.hd, 1);
+  });
+  it('isValid: 1444/9/1 = true', () => {
+    assert.equal(isValidHijriDate(1444, 9, 1), true);
+  });
+  it('isValid: 1317/1/1 = false', () => {
+    assert.equal(isValidHijriDate(1317, 1, 1), false);
+  });
+  it('daysInMonth: Ramadan 1444 = 29', () => {
+    assert.equal(daysInHijriMonth(1444, 9), 29);
+  });
 });

-// FCNA conversions
-test('CJS FCNA toGregorian: 1446/9/1 = 2025-03-01', () => {
-  const d = toGregorian(1446, 9, 1, { calendar: 'fcna' });
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
-});
-test('CJS FCNA toHijri: 2025-03-01 = 1446/9/1', () => {
-  const h = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
-  assert.ok(h !== null);
-  assert.equal(h.hy, 1446);
-  assert.equal(h.hm, 9);
-  assert.equal(h.hd, 1);
+// ─── Invalid month validation ───────────────────────────────────────────────
+
+describe('CJS invalid month', () => {
+  it('daysInMonth throws for month 0', () => {
+    assert.throws(() => daysInHijriMonth(1444, 0), /month must be 1-12/);
+  });
+  it('daysInMonth throws for month 13', () => {
+    assert.throws(() => daysInHijriMonth(1444, 13), /month must be 1-12/);
+  });
+  it('isValid: month 13 = false', () => {
+    assert.equal(isValidHijriDate(1444, 13, 1), false);
+  });
 });

-// Registry
-test('CJS listCalendars includes uaq and fcna', () => {
-  const cals = listCalendars();
-  assert.ok(cals.includes('uaq'));
-  assert.ok(cals.includes('fcna'));
-});
-test('CJS getCalendar throws for unknown', () => {
-  assert.throws(
-    () => getCalendar('nope'),
-    /Unknown Hijri calendar/,
-  );
+// ─── FCNA conversions ───────────────────────────────────────────────────────
+
+describe('CJS FCNA conversions', () => {
+  it('toGregorian: 1446/9/1 = 2025-03-01', () => {
+    const d = toGregorian(1446, 9, 1, { calendar: 'fcna' });
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
+  });
+  it('toHijri: 2025-03-01 = 1446/9/1', () => {
+    const h = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
+    assert.ok(h !== null);
+    assert.equal(h.hy, 1446);
+    assert.equal(h.hm, 9);
+    assert.equal(h.hd, 1);
+  });
 });

-// Custom calendar
-test('CJS registerCalendar: custom engine', () => {
-  const mockEngine = {
-    id: 'mock-cjs',
-    toHijri: () => ({ hy: 888, hm: 2, hd: 5 }),
-    toGregorian: () => new Date(Date.UTC(2001, 0, 1)),
-    isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1,
-    daysInMonth: () => 29,
-  };
-  registerCalendar('mock-cjs', mockEngine);
+// ─── Registry ───────────────────────────────────────────────────────────────

-  const h = toHijri(new Date(2020, 0, 1), { calendar: 'mock-cjs' });
-  assert.ok(h !== null);
-  assert.equal(h.hy, 888);
-  assert.equal(h.hm, 2);
-  assert.equal(h.hd, 5);
+describe('CJS registry', () => {
+  it('listCalendars includes uaq and fcna', () => {
+    const cals = listCalendars();
+    assert.ok(cals.includes('uaq'));
+    assert.ok(cals.includes('fcna'));
+  });
+  it('getCalendar throws for unknown', () => {
+    assert.throws(() => getCalendar('nope'), /Unknown Hijri calendar/);
+  });
+  it('registerCalendar: custom engine', () => {
+    const mockEngine = {
+      id: 'mock-cjs',
+      toHijri: () => ({ hy: 888, hm: 2, hd: 5 }),
+      toGregorian: () => new Date(Date.UTC(2001, 0, 1)),
+      isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1,
+      daysInMonth: () => 29,
+    };
+    registerCalendar('mock-cjs', mockEngine);
+
+    const h = toHijri(new Date(2020, 0, 1), { calendar: 'mock-cjs' });
+    assert.ok(h !== null);
+    assert.equal(h.hy, 888);
+    assert.equal(h.hm, 2);
+    assert.equal(h.hd, 5);
+  });
 });

-// Error cases
-test('CJS toHijri throws on non-Date', () => {
-  assert.throws(() => toHijri('bad'), /Invalid Gregorian date/);
-});
-test('CJS toGregorian returns null for out-of-range date', () => {
-  assert.strictEqual(toGregorian(1317, 1, 1), null);
-});
+// ─── Error cases ────────────────────────────────────────────────────────────

-// Summary
-const total = passed + failed;
-console.log(`\n${total} tests total: ${passed} passed, ${failed} failed`);
-if (failed > 0) process.exit(1);
+describe('CJS error cases', () => {
+  it('toHijri throws on non-Date', () => {
+    assert.throws(() => toHijri('bad'), /Invalid Gregorian date/);
+  });
+  it('toGregorian returns null for out-of-range date', () => {
+    assert.strictEqual(toGregorian(1317, 1, 1), null);
+  });
+});
--- a/test.mjs
+++ b/test.mjs
@ -1,6 +1,6 @@
 // ESM test suite for hijri-core.
-// Uses Node.js assert — no test framework needed.

+import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import {
  toHijri,
@ -19,250 +19,255 @@ import {
  hwNumeric,
 } from './dist/index.mjs';

-let passed = 0;
-let failed = 0;
+// ─── Exports exist ──────────────────────────────────────────────────────────

-function test(name, fn) {
-  try {
-    fn();
-    console.log(`[${name}]... PASS`);
-    passed++;
-  } catch (err) {
-    console.error(`[${name}]... FAIL: ${err.message}`);
-    failed++;
-  }
-}
-
-// ─── 1. Exports exist ─────────────────────────────────────────────────────────
-
-test('exports: toHijri is a function', () => {
-  assert.equal(typeof toHijri, 'function');
-});
-test('exports: toGregorian is a function', () => {
-  assert.equal(typeof toGregorian, 'function');
-});
-test('exports: isValidHijriDate is a function', () => {
-  assert.equal(typeof isValidHijriDate, 'function');
-});
-test('exports: daysInHijriMonth is a function', () => {
-  assert.equal(typeof daysInHijriMonth, 'function');
-});
-test('exports: registerCalendar is a function', () => {
-  assert.equal(typeof registerCalendar, 'function');
-});
-test('exports: getCalendar is a function', () => {
-  assert.equal(typeof getCalendar, 'function');
-});
-test('exports: listCalendars is a function', () => {
-  assert.equal(typeof listCalendars, 'function');
-});
-test('exports: hDatesTable is an array', () => {
-  assert.ok(Array.isArray(hDatesTable));
-  assert.ok(hDatesTable.length > 180);
-});
-test('exports: hmLong has 12 entries', () => {
-  assert.equal(hmLong.length, 12);
-});
-test('exports: hmMedium has 12 entries', () => {
-  assert.equal(hmMedium.length, 12);
-});
-test('exports: hmShort has 12 entries', () => {
-  assert.equal(hmShort.length, 12);
-});
-test('exports: hwLong has 7 entries', () => {
-  assert.equal(hwLong.length, 7);
-});
-test('exports: hwShort has 7 entries', () => {
-  assert.equal(hwShort.length, 7);
-});
-test('exports: hwNumeric has 7 entries', () => {
-  assert.equal(hwNumeric.length, 7);
-  assert.deepEqual(hwNumeric, [1, 2, 3, 4, 5, 6, 7]);
+describe('exports', () => {
+  it('toHijri is a function', () => {
+    assert.equal(typeof toHijri, 'function');
+  });
+  it('toGregorian is a function', () => {
+    assert.equal(typeof toGregorian, 'function');
+  });
+  it('isValidHijriDate is a function', () => {
+    assert.equal(typeof isValidHijriDate, 'function');
+  });
+  it('daysInHijriMonth is a function', () => {
+    assert.equal(typeof daysInHijriMonth, 'function');
+  });
+  it('registerCalendar is a function', () => {
+    assert.equal(typeof registerCalendar, 'function');
+  });
+  it('getCalendar is a function', () => {
+    assert.equal(typeof getCalendar, 'function');
+  });
+  it('listCalendars is a function', () => {
+    assert.equal(typeof listCalendars, 'function');
+  });
+  it('hDatesTable is an array with > 180 entries', () => {
+    assert.ok(Array.isArray(hDatesTable));
+    assert.ok(hDatesTable.length > 180);
+  });
+  it('hmLong has 12 entries', () => {
+    assert.equal(hmLong.length, 12);
+  });
+  it('hmMedium has 12 entries', () => {
+    assert.equal(hmMedium.length, 12);
+  });
+  it('hmShort has 12 entries', () => {
+    assert.equal(hmShort.length, 12);
+  });
+  it('hwLong has 7 entries', () => {
+    assert.equal(hwLong.length, 7);
+  });
+  it('hwShort has 7 entries', () => {
+    assert.equal(hwShort.length, 7);
+  });
+  it('hwNumeric has 7 entries [1..7]', () => {
+    assert.equal(hwNumeric.length, 7);
+    assert.deepEqual(hwNumeric, [1, 2, 3, 4, 5, 6, 7]);
+  });
 });

-// ─── 2. UAQ toGregorian ───────────────────────────────────────────────────────
+// ─── UAQ toGregorian ────────────────────────────────────────────────────────

-test('UAQ toGregorian: 1444/9/1 = 2023-03-23', () => {
-  const d = toGregorian(1444, 9, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2023-03-23');
-});
-test('UAQ toGregorian: 1446/9/1 = 2025-03-01', () => {
-  const d = toGregorian(1446, 9, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
-});
-test('UAQ toGregorian: 1446/10/1 = 2025-03-30', () => {
-  const d = toGregorian(1446, 10, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-30');
-});
-test('UAQ toGregorian: 1318/1/1 = 1900-04-30', () => {
-  const d = toGregorian(1318, 1, 1);
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '1900-04-30');
+describe('UAQ toGregorian', () => {
+  it('1444/9/1 = 2023-03-23', () => {
+    const d = toGregorian(1444, 9, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2023-03-23');
+  });
+  it('1446/9/1 = 2025-03-01', () => {
+    const d = toGregorian(1446, 9, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
+  });
+  it('1446/10/1 = 2025-03-30', () => {
+    const d = toGregorian(1446, 10, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-30');
+  });
+  it('1318/1/1 = 1900-04-30', () => {
+    const d = toGregorian(1318, 1, 1);
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '1900-04-30');
+  });
 });

-// ─── 3. UAQ toHijri ───────────────────────────────────────────────────────────
+// ─── UAQ toHijri ────────────────────────────────────────────────────────────

-test('UAQ toHijri: 2023-03-23 = 1444/9/1', () => {
-  const h = toHijri(new Date(2023, 2, 23, 12));
-  assert.ok(h !== null);
-  assert.equal(h.hy, 1444);
-  assert.equal(h.hm, 9);
-  assert.equal(h.hd, 1);
-});
-test('UAQ toHijri: 2025-03-01 = 1446/9/1', () => {
-  const h = toHijri(new Date(2025, 2, 1, 12));
-  assert.ok(h !== null);
-  assert.equal(h.hy, 1446);
-  assert.equal(h.hm, 9);
-  assert.equal(h.hd, 1);
+describe('UAQ toHijri', () => {
+  it('2023-03-23 = 1444/9/1', () => {
+    const h = toHijri(new Date(2023, 2, 23, 12));
+    assert.ok(h !== null);
+    assert.equal(h.hy, 1444);
+    assert.equal(h.hm, 9);
+    assert.equal(h.hd, 1);
+  });
+  it('2025-03-01 = 1446/9/1', () => {
+    const h = toHijri(new Date(2025, 2, 1, 12));
+    assert.ok(h !== null);
+    assert.equal(h.hy, 1446);
+    assert.equal(h.hm, 9);
+    assert.equal(h.hd, 1);
+  });
 });

-// ─── 4. UAQ isValidHijriDate ──────────────────────────────────────────────────
+// ─── UAQ isValidHijriDate ───────────────────────────────────────────────────

-test('UAQ isValid: 1444/9/1 = true', () => {
-  assert.equal(isValidHijriDate(1444, 9, 1), true);
-});
-test('UAQ isValid: 1317/1/1 = false (before table)', () => {
-  assert.equal(isValidHijriDate(1317, 1, 1), false);
-});
-test('UAQ isValid: 1501/1/1 = false (sentinel)', () => {
-  assert.equal(isValidHijriDate(1501, 1, 1), false);
-});
-test('UAQ isValid: month 0 = false', () => {
-  assert.equal(isValidHijriDate(1444, 0, 1), false);
+describe('UAQ isValid', () => {
+  it('1444/9/1 = true', () => {
+    assert.equal(isValidHijriDate(1444, 9, 1), true);
+  });
+  it('1317/1/1 = false (before table)', () => {
+    assert.equal(isValidHijriDate(1317, 1, 1), false);
+  });
+  it('1501/1/1 = false (sentinel)', () => {
+    assert.equal(isValidHijriDate(1501, 1, 1), false);
+  });
+  it('month 0 = false', () => {
+    assert.equal(isValidHijriDate(1444, 0, 1), false);
+  });
+  it('month 13 = false', () => {
+    assert.equal(isValidHijriDate(1444, 13, 1), false);
+  });
 });

-// ─── 5. daysInHijriMonth ──────────────────────────────────────────────────────
+// ─── daysInHijriMonth ───────────────────────────────────────────────────────

-test('UAQ daysInMonth: Ramadan 1444 = 29 days', () => {
-  // 1444 dpm = 0x0A9A; bit 8 (month 9) = (0x0A9A >> 8) & 1 = 0x0A & 1 = 0 -> 29
-  assert.equal(daysInHijriMonth(1444, 9), 29);
+describe('UAQ daysInMonth', () => {
+  it('Ramadan 1444 = 29 days', () => {
+    assert.equal(daysInHijriMonth(1444, 9), 29);
+  });
+  it('throws for month 0', () => {
+    assert.throws(() => daysInHijriMonth(1444, 0), /month must be 1-12/);
+  });
+  it('throws for month 13', () => {
+    assert.throws(() => daysInHijriMonth(1444, 13), /month must be 1-12/);
+  });
 });

-// ─── 6. FCNA toGregorian ──────────────────────────────────────────────────────
+// ─── FCNA toGregorian ───────────────────────────────────────────────────────

-test('FCNA toGregorian: 1446/9/1 = 2025-03-01', () => {
-  const d = toGregorian(1446, 9, 1, { calendar: 'fcna' });
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
-});
-test('FCNA toGregorian: 1446/10/1 = 2025-03-30', () => {
-  const d = toGregorian(1446, 10, 1, { calendar: 'fcna' });
-  assert.ok(d instanceof Date);
-  assert.equal(d.toISOString().slice(0, 10), '2025-03-30');
+describe('FCNA toGregorian', () => {
+  it('1446/9/1 = 2025-03-01', () => {
+    const d = toGregorian(1446, 9, 1, { calendar: 'fcna' });
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-01');
+  });
+  it('1446/10/1 = 2025-03-30', () => {
+    const d = toGregorian(1446, 10, 1, { calendar: 'fcna' });
+    assert.ok(d instanceof Date);
+    assert.equal(d.toISOString().slice(0, 10), '2025-03-30');
+  });
 });

-// ─── 7. FCNA toHijri ──────────────────────────────────────────────────────────
+// ─── FCNA toHijri ───────────────────────────────────────────────────────────

-test('FCNA toHijri: 2025-03-01 = 1446/9/1', () => {
-  // Use UTC date for FCNA (criterion is UTC-based).
-  const h = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
-  assert.ok(h !== null);
-  assert.equal(h.hy, 1446);
-  assert.equal(h.hm, 9);
-  assert.equal(h.hd, 1);
+describe('FCNA toHijri', () => {
+  it('2025-03-01 = 1446/9/1', () => {
+    const h = toHijri(new Date('2025-03-01'), { calendar: 'fcna' });
+    assert.ok(h !== null);
+    assert.equal(h.hy, 1446);
+    assert.equal(h.hm, 9);
+    assert.equal(h.hd, 1);
+  });
 });

-// ─── 8. FCNA round-trips ──────────────────────────────────────────────────────
+// ─── FCNA round-trips ───────────────────────────────────────────────────────

-test('FCNA round-trip: 1446/9/1 toGregorian->toHijri', () => {
-  const greg = toGregorian(1446, 9, 1, { calendar: 'fcna' });
-  assert.ok(greg !== null);
-  const hijri = toHijri(greg, { calendar: 'fcna' });
-  assert.ok(hijri !== null);
-  assert.equal(hijri.hy, 1446);
-  assert.equal(hijri.hm, 9);
-  assert.equal(hijri.hd, 1);
-});
-test('FCNA round-trip: 1446/10/15 toGregorian->toHijri', () => {
-  const greg = toGregorian(1446, 10, 15, { calendar: 'fcna' });
-  assert.ok(greg !== null);
-  const hijri = toHijri(greg, { calendar: 'fcna' });
-  assert.ok(hijri !== null);
-  assert.equal(hijri.hy, 1446);
-  assert.equal(hijri.hm, 10);
-  assert.equal(hijri.hd, 15);
+describe('FCNA round-trips', () => {
+  it('1446/9/1 toGregorian->toHijri', () => {
+    const greg = toGregorian(1446, 9, 1, { calendar: 'fcna' });
+    assert.ok(greg !== null);
+    const hijri = toHijri(greg, { calendar: 'fcna' });
+    assert.ok(hijri !== null);
+    assert.equal(hijri.hy, 1446);
+    assert.equal(hijri.hm, 9);
+    assert.equal(hijri.hd, 1);
+  });
+  it('1446/10/15 toGregorian->toHijri', () => {
+    const greg = toGregorian(1446, 10, 15, { calendar: 'fcna' });
+    assert.ok(greg !== null);
+    const hijri = toHijri(greg, { calendar: 'fcna' });
+    assert.ok(hijri !== null);
+    assert.equal(hijri.hy, 1446);
+    assert.equal(hijri.hm, 10);
+    assert.equal(hijri.hd, 15);
+  });
 });

-// ─── 9. FCNA isValid ──────────────────────────────────────────────────────────
+// ─── FCNA isValid ───────────────────────────────────────────────────────────

-test('FCNA isValid: 1/1/1 = true', () => {
-  assert.equal(isValidHijriDate(1, 1, 1, { calendar: 'fcna' }), true);
-});
-test('FCNA isValid: 1600/1/1 = true', () => {
-  assert.equal(isValidHijriDate(1600, 1, 1, { calendar: 'fcna' }), true);
-});
-test('FCNA isValid: 0/1/1 = false', () => {
-  assert.equal(isValidHijriDate(0, 1, 1, { calendar: 'fcna' }), false);
+describe('FCNA isValid', () => {
+  it('1/1/1 = true', () => {
+    assert.equal(isValidHijriDate(1, 1, 1, { calendar: 'fcna' }), true);
+  });
+  it('1600/1/1 = true', () => {
+    assert.equal(isValidHijriDate(1600, 1, 1, { calendar: 'fcna' }), true);
+  });
+  it('0/1/1 = false', () => {
+    assert.equal(isValidHijriDate(0, 1, 1, { calendar: 'fcna' }), false);
+  });
 });

-// ─── 10. listCalendars ────────────────────────────────────────────────────────
+// ─── FCNA daysInMonth invalid month ─────────────────────────────────────────

-test('listCalendars includes uaq and fcna', () => {
-  const cals = listCalendars();
-  assert.ok(cals.includes('uaq'));
-  assert.ok(cals.includes('fcna'));
+describe('FCNA daysInMonth', () => {
+  it('throws for month 0', () => {
+    assert.throws(() => daysInHijriMonth(1446, 0, { calendar: 'fcna' }), /month must be 1-12/);
+  });
+  it('throws for month 13', () => {
+    assert.throws(() => daysInHijriMonth(1446, 13, { calendar: 'fcna' }), /month must be 1-12/);
+  });
 });

-// ─── 11. getCalendar throws for unknown ───────────────────────────────────────
+// ─── Registry ───────────────────────────────────────────────────────────────

-test('getCalendar throws for unknown calendar', () => {
-  assert.throws(
-    () => getCalendar('nonexistent'),
-    /Unknown Hijri calendar/,
-  );
+describe('registry', () => {
+  it('listCalendars includes uaq and fcna', () => {
+    const cals = listCalendars();
+    assert.ok(cals.includes('uaq'));
+    assert.ok(cals.includes('fcna'));
+  });
+  it('getCalendar throws for unknown calendar', () => {
+    assert.throws(() => getCalendar('nonexistent'), /Unknown Hijri calendar/);
+  });
+  it('registerCalendar: custom engine works', () => {
+    const mockEngine = {
+      id: 'mock',
+      toHijri: (_date) => ({ hy: 999, hm: 1, hd: 1 }),
+      toGregorian: (_hy, _hm, _hd) => new Date(Date.UTC(2000, 0, 1)),
+      isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1,
+      daysInMonth: (_hy, _hm) => 30,
+    };
+    registerCalendar('mock', mockEngine);
+
+    const cals = listCalendars();
+    assert.ok(cals.includes('mock'));
+
+    const h = toHijri(new Date(2020, 0, 1), { calendar: 'mock' });
+    assert.ok(h !== null);
+    assert.equal(h.hy, 999);
+
+    const g = toGregorian(1, 1, 1, { calendar: 'mock' });
+    assert.ok(g instanceof Date);
+    assert.equal(g.toISOString().slice(0, 10), '2000-01-01');
+
+    assert.equal(isValidHijriDate(1, 1, 1, { calendar: 'mock' }), true);
+    assert.equal(daysInHijriMonth(1, 1, { calendar: 'mock' }), 30);
+  });
 });

-// ─── 12. Custom calendar registration ────────────────────────────────────────
+// ─── Error cases ────────────────────────────────────────────────────────────

-test('registerCalendar: custom engine works', () => {
-  const mockEngine = {
-    id: 'mock',
-    toHijri: (_date) => ({ hy: 999, hm: 1, hd: 1 }),
-    toGregorian: (_hy, _hm, _hd) => new Date(Date.UTC(2000, 0, 1)),
-    isValid: (hy, hm, hd) => hy > 0 && hm >= 1 && hm <= 12 && hd >= 1,
-    daysInMonth: (_hy, _hm) => 30,
-  };
-  registerCalendar('mock', mockEngine);
-
-  const cals = listCalendars();
-  assert.ok(cals.includes('mock'));
-
-  const h = toHijri(new Date(2020, 0, 1), { calendar: 'mock' });
-  assert.ok(h !== null);
-  assert.equal(h.hy, 999);
-
-  const g = toGregorian(1, 1, 1, { calendar: 'mock' });
-  assert.ok(g instanceof Date);
-  assert.equal(g.toISOString().slice(0, 10), '2000-01-01');
-
-  assert.equal(isValidHijriDate(1, 1, 1, { calendar: 'mock' }), true);
-  assert.equal(daysInHijriMonth(1, 1, { calendar: 'mock' }), 30);
+describe('error cases', () => {
+  it('toHijri throws on non-Date input', () => {
+    assert.throws(() => toHijri('2023-03-23'), /Invalid Gregorian date/);
+  });
+  it('toHijri throws on invalid Date', () => {
+    assert.throws(() => toHijri(new Date('invalid')), /Invalid Gregorian date/);
+  });
+  it('UAQ toGregorian returns null for out-of-range date', () => {
+    assert.strictEqual(toGregorian(1317, 1, 1), null);
+  });
 });
-
-// ─── 13. Error cases ──────────────────────────────────────────────────────────
-
-test('toHijri throws on non-Date input', () => {
-  assert.throws(
-    () => toHijri('2023-03-23'),
-    /Invalid Gregorian date/,
-  );
-});
-test('toHijri throws on invalid Date', () => {
-  assert.throws(
-    () => toHijri(new Date('invalid')),
-    /Invalid Gregorian date/,
-  );
-});
-test('UAQ toGregorian returns null for out-of-range date', () => {
-  assert.strictEqual(toGregorian(1317, 1, 1), null);
-});
-
-// ─── Summary ─────────────────────────────────────────────────────────────────
-
-const total = passed + failed;
-console.log(`\n${total} tests total: ${passed} passed, ${failed} failed`);
-if (failed > 0) process.exit(1);
--- a/tsconfig.json
+++ b/tsconfig.json
@ -9,9 +9,12 @@
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
    "outDir": "dist",
    "rootDir": "src",
    "types": ["node"]
  },
-  "include": ["src"]
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
 }