refactor: code quality improvements across the board

- Add input validation (TypeError) to cycleMonth and cycleYear - Convert tests to node:test runner with describe/it structure - Add ESLint + Prettier with lint, format, and format:check scripts - Update CI workflow with lint job, frozen-lockfile, and pack-check - Add noImplicitReturns, noFallthroughCasesInSwitch, skipLibCheck to tsconfig - Add invalid Date tests for both ESM and CJS suites
2026-06-30 18:54:29 +00:00 · 2026-03-08 11:32:47 -04:00 · 2026-03-08 11:32:47 -04:00 · 9b9abb99c8
commit 9b9abb99c8
parent 24db90e9f5
12 changed files with 1050 additions and 310 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -8,95 +8,76 @@ on:

 jobs:
  test:
-    name: Test (Node ${{ matrix.node-version }})
+    name: Test (Node ${{ matrix.node }})
    runs-on: ubuntu-latest
    strategy:
      matrix:
-        node-version: [20, 22, 24]
-
+        node: [20, 22, 24]
    steps:
      - uses: actions/checkout@v4
-
      - uses: pnpm/action-setup@v4
        with:
          version: 10
-
-      - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v4
+      - uses: actions/setup-node@v4
        with:
-          node-version: ${{ matrix.node-version }}
+          node-version: ${{ matrix.node }}
          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm build
+      - run: node --test test.mjs
+      - run: node --test test-cjs.cjs

-      - name: Install dependencies
-        run: pnpm install
-
-      - name: Build
-        run: pnpm build
-
-      - name: Test (ESM)
-        run: node test.mjs
-
-      - name: Test (CJS)
-        run: node test-cjs.cjs
+  lint:
+    name: Lint & Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
+      - 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: Type Check
+    name: Typecheck
    runs-on: ubuntu-latest
-
    steps:
      - uses: actions/checkout@v4
-
      - uses: pnpm/action-setup@v4
        with:
          version: 10
-
-      - name: Use Node.js 24
-        uses: actions/setup-node@v4
+      - uses: actions/setup-node@v4
        with:
          node-version: 24
          cache: pnpm
-
-      - name: Install dependencies
-        run: pnpm install
-
-      - name: Type check
-        run: pnpm typecheck
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm run typecheck

  pack-check:
-    name: Pack Check
+    name: Pack check
    runs-on: ubuntu-latest
-
    steps:
      - uses: actions/checkout@v4
-
      - uses: pnpm/action-setup@v4
        with:
          version: 10
-
-      - name: Use Node.js 24
-        uses: actions/setup-node@v4
+      - uses: actions/setup-node@v4
        with:
          node-version: 24
          cache: pnpm
-
-      - name: Install dependencies
-        run: pnpm install
-
-      - name: Build
-        run: pnpm build
-
-      - name: Check pack contents
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm build
+      - name: Verify pack contents
        run: |
-          npm pack --dry-run 2>&1 | tee pack-output.txt
-          # Verify expected files are present
-          grep -q "dist/index.cjs" pack-output.txt
-          grep -q "dist/index.mjs" pack-output.txt
-          grep -q "dist/index.d.ts" pack-output.txt
-          grep -q "dist/index.d.mts" pack-output.txt
-          grep -q "README.md" pack-output.txt
-          grep -q "LICENSE" pack-output.txt
-          grep -q "CHANGELOG.md" pack-output.txt
-          # Verify image folders are NOT in the pack
-          ! grep -q "mm-256" pack-output.txt
-          ! grep -q "my-256" pack-output.txt
+          PACK=$(npm pack --dry-run 2>&1)
+          echo "$PACK"
+          for f in dist/index.cjs dist/index.mjs dist/index.d.ts dist/index.d.mts README.md LICENSE CHANGELOG.md; do
+            echo "$PACK" | grep -q "$f" || (echo "Missing: $f" && exit 1)
+          done
+          echo "$PACK" | grep -q "src/" && (echo "ERROR: src/ should not be in pack" && exit 1) || true
          echo "Pack check passed"
--- a/.gitignore
+++ b/.gitignore
@ -56,3 +56,9 @@ coverage/
 .windsurf/
 .cody/
 .sourcegraph/
+.vscode/*
+.codex/
+.aider/
+.aider.chat.history.md
+.continue/
+.gemini/
--- a/.prettierrc
+++ b/.prettierrc
@ -0,0 +1,6 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 100,
+  "tabWidth": 2
+}
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@ -0,0 +1,12 @@
+import eslint from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import prettier from 'eslint-config-prettier';
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  ...tseslint.configs.recommended,
+  prettier,
+  {
+    ignores: ['dist/', 'node_modules/', 'test.mjs', 'test-cjs.cjs'],
+  },
+);
--- a/package.json
+++ b/package.json
@ -29,8 +29,11 @@
  "scripts": {
    "build": "tsup",
    "typecheck": "tsc --noEmit",
+    "lint": "eslint src/",
+    "format": "prettier --write src/ test.mjs test-cjs.cjs eslint.config.mjs tsup.config.ts",
+    "format:check": "prettier --check src/ test.mjs test-cjs.cjs eslint.config.mjs tsup.config.ts",
    "pretest": "tsup",
-    "test": "node test.mjs && node test-cjs.cjs",
+    "test": "node --test test.mjs && node --test test-cjs.cjs",
    "prepublishOnly": "tsup"
  },
  "engines": {
@ -62,8 +65,13 @@
    "registry": "https://registry.npmjs.org/"
  },
  "devDependencies": {
+    "@eslint/js": "^10.0.1",
    "@types/node": "^22.0.0",
+    "eslint": "^10.0.3",
+    "eslint-config-prettier": "^10.1.8",
+    "prettier": "^3.8.1",
    "tsup": "^8.0.0",
-    "typescript": "^5.0.0"
+    "typescript": "^5.0.0",
+    "typescript-eslint": "^8.56.1"
  }
 }
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@ -8,15 +8,30 @@ importers:

  .:
    devDependencies:
+      '@eslint/js':
+        specifier: ^10.0.1
+        version: 10.0.1(eslint@10.0.3)
      '@types/node':
        specifier: ^22.0.0
        version: 22.19.11
+      eslint:
+        specifier: ^10.0.3
+        version: 10.0.3
+      eslint-config-prettier:
+        specifier: ^10.1.8
+        version: 10.1.8(eslint@10.0.3)
+      prettier:
+        specifier: ^3.8.1
+        version: 3.8.1
      tsup:
        specifier: ^8.0.0
        version: 8.5.1(typescript@5.9.3)
      typescript:
        specifier: ^5.0.0
        version: 5.9.3
+      typescript-eslint:
+        specifier: ^8.56.1
+        version: 8.56.1(eslint@10.0.3)(typescript@5.9.3)

 packages:

@ -176,6 +191,61 @@ packages:
    cpu: [x64]
    os: [win32]

+  '@eslint-community/eslint-utils@4.9.1':
+    resolution: {integrity: sha512-phrYmNiYppR7znFEdqgfWHXR6NCkZEK7hwWDHZUjit/2/U0r6XvkDl0SYnoM51Hq7FhCGdLDT6zxCCOY1hexsQ==}
+    engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
+    peerDependencies:
+      eslint: ^6.0.0 || ^7.0.0 || >=8.0.0
+
+  '@eslint-community/regexpp@4.12.2':
+    resolution: {integrity: sha512-EriSTlt5OC9/7SXkRSCAhfSxxoSUgBm33OH+IkwbdpgoqsSsUg7y3uh+IICI/Qg4BBWr3U2i39RpmycbxMq4ew==}
+    engines: {node: ^12.0.0 || ^14.0.0 || >=16.0.0}
+
+  '@eslint/config-array@0.23.3':
+    resolution: {integrity: sha512-j+eEWmB6YYLwcNOdlwQ6L2OsptI/LO6lNBuLIqe5R7RetD658HLoF+Mn7LzYmAWWNNzdC6cqP+L6r8ujeYXWLw==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@eslint/config-helpers@0.5.3':
+    resolution: {integrity: sha512-lzGN0onllOZCGroKJmRwY6QcEHxbjBw1gwB8SgRSqK8YbbtEXMvKynsXc3553ckIEBxsbMBU7oOZXKIPGZNeZw==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@eslint/core@1.1.1':
+    resolution: {integrity: sha512-QUPblTtE51/7/Zhfv8BDwO0qkkzQL7P/aWWbqcf4xWLEYn1oKjdO0gglQBB4GAsu7u6wjijbCmzsUTy6mnk6oQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@eslint/js@10.0.1':
+    resolution: {integrity: sha512-zeR9k5pd4gxjZ0abRoIaxdc7I3nDktoXZk2qOv9gCNWx3mVwEn32VRhyLaRsDiJjTs0xq/T8mfPtyuXu7GWBcA==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+    peerDependencies:
+      eslint: ^10.0.0
+    peerDependenciesMeta:
+      eslint:
+        optional: true
+
+  '@eslint/object-schema@3.0.3':
+    resolution: {integrity: sha512-iM869Pugn9Nsxbh/YHRqYiqd23AmIbxJOcpUMOuWCVNdoQJ5ZtwL6h3t0bcZzJUlC3Dq9jCFCESBZnX0GTv7iQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@eslint/plugin-kit@0.6.1':
+    resolution: {integrity: sha512-iH1B076HoAshH1mLpHMgwdGeTs0CYwL0SPMkGuSebZrwBp16v415e9NZXg2jtrqPVQjf6IANe2Vtlr5KswtcZQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  '@humanfs/core@0.19.1':
+    resolution: {integrity: sha512-5DyQ4+1JEUzejeK1JGICcideyfUbGixgS9jNgex5nqkW+cY7WZhxBigmieN5Qnw9ZosSNVC9KQKyb+GUaGyKUA==}
+    engines: {node: '>=18.18.0'}
+
+  '@humanfs/node@0.16.7':
+    resolution: {integrity: sha512-/zUx+yOsIrG4Y43Eh2peDeKCxlRt/gET6aHfaKpuq267qXdYDFViVHfMaLyygZOnl0kGWxFIgsBy8QFuTLUXEQ==}
+    engines: {node: '>=18.18.0'}
+
+  '@humanwhocodes/module-importer@1.0.1':
+    resolution: {integrity: sha512-bxveV4V8v5Yb4ncFTT3rPSgZBOpCkjfK0y4oVVVJwIuDVBRMDXrPyXRL988i5ap9m9bnyEEjWfm5WkBmtffLfA==}
+    engines: {node: '>=12.22'}
+
+  '@humanwhocodes/retry@0.4.3':
+    resolution: {integrity: sha512-bV0Tgo9K4hfPCek+aMAn81RppFKv2ySDQeMoSZuvTASywNTnVJCArCZE2FWqpvIatKu7VMRLWlR1EazvVhDyhQ==}
+    engines: {node: '>=18.18'}
+
  '@jridgewell/gen-mapping@0.3.13':
    resolution: {integrity: sha512-2kkt/7niJ6MgEPxF0bYdQ6etZaA+fQvDcLKckhy1yIQOzaoKjBBjSj63/aLVjYE3qhRt5dvM+uUyfCg6UKCBbA==}

@ -327,20 +397,101 @@ packages:
    cpu: [x64]
    os: [win32]

+  '@types/esrecurse@4.3.1':
+    resolution: {integrity: sha512-xJBAbDifo5hpffDBuHl0Y8ywswbiAp/Wi7Y/GtAgSlZyIABppyurxVueOPE8LUQOxdlgi6Zqce7uoEpqNTeiUw==}
+
  '@types/estree@1.0.8':
    resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}

+  '@types/json-schema@7.0.15':
+    resolution: {integrity: sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==}
+
  '@types/node@22.19.11':
    resolution: {integrity: sha512-BH7YwL6rA93ReqeQS1c4bsPpcfOmJasG+Fkr6Y59q83f9M1WcBRHR2vM+P9eOisYRcN3ujQoiZY8uk5W+1WL8w==}

+  '@typescript-eslint/eslint-plugin@8.56.1':
+    resolution: {integrity: sha512-Jz9ZztpB37dNC+HU2HI28Bs9QXpzCz+y/twHOwhyrIRdbuVDxSytJNDl6z/aAKlaRIwC7y8wJdkBv7FxYGgi0A==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      '@typescript-eslint/parser': ^8.56.1
+      eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/parser@8.56.1':
+    resolution: {integrity: sha512-klQbnPAAiGYFyI02+znpBRLyjL4/BrBd0nyWkdC0s/6xFLkXYQ8OoRrSkqacS1ddVxf/LDyODIKbQ5TgKAf/Fg==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/project-service@8.56.1':
+    resolution: {integrity: sha512-TAdqQTzHNNvlVFfR+hu2PDJrURiwKsUvxFn1M0h95BB8ah5jejas08jUWG4dBA68jDMI988IvtfdAI53JzEHOQ==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/scope-manager@8.56.1':
+    resolution: {integrity: sha512-YAi4VDKcIZp0O4tz/haYKhmIDZFEUPOreKbfdAN3SzUDMcPhJ8QI99xQXqX+HoUVq8cs85eRKnD+rne2UAnj2w==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+
+  '@typescript-eslint/tsconfig-utils@8.56.1':
+    resolution: {integrity: sha512-qOtCYzKEeyr3aR9f28mPJqBty7+DBqsdd63eO0yyDwc6vgThj2UjWfJIcsFeSucYydqcuudMOprZ+x1SpF3ZuQ==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/type-utils@8.56.1':
+    resolution: {integrity: sha512-yB/7dxi7MgTtGhZdaHCemf7PuwrHMenHjmzgUW1aJpO+bBU43OycnM3Wn+DdvDO/8zzA9HlhaJ0AUGuvri4oGg==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/types@8.56.1':
+    resolution: {integrity: sha512-dbMkdIUkIkchgGDIv7KLUpa0Mda4IYjo4IAMJUZ+3xNoUXxMsk9YtKpTHSChRS85o+H9ftm51gsK1dZReY9CVw==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+
+  '@typescript-eslint/typescript-estree@8.56.1':
+    resolution: {integrity: sha512-qzUL1qgalIvKWAf9C1HpvBjif+Vm6rcT5wZd4VoMb9+Km3iS3Cv9DY6dMRMDtPnwRAFyAi7YXJpTIEXLvdfPxg==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/utils@8.56.1':
+    resolution: {integrity: sha512-HPAVNIME3tABJ61siYlHzSWCGtOoeP2RTIaHXFMPqjrQKCGB9OgUVdiNgH7TJS2JNIQ5qQ4RsAUDuGaGme/KOA==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
+      typescript: '>=4.8.4 <6.0.0'
+
+  '@typescript-eslint/visitor-keys@8.56.1':
+    resolution: {integrity: sha512-KiROIzYdEV85YygXw6BI/Dx4fnBlFQu6Mq4QE4MOH9fFnhohw6wX/OAvDY2/C+ut0I3RSPKenvZJIVYqJNkhEw==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+
+  acorn-jsx@5.3.2:
+    resolution: {integrity: sha512-rq9s+JNhf0IChjtDXxllJ7g41oZk5SlXtp0LHwyA5cejwn7vKmKp4pPri6YEePv2PU65sAsegbXtIinmDFDXgQ==}
+    peerDependencies:
+      acorn: ^6.0.0 || ^7.0.0 || ^8.0.0
+
  acorn@8.16.0:
    resolution: {integrity: sha512-UVJyE9MttOsBQIDKw1skb9nAwQuR5wuGD3+82K6JgJlm/Y+KI92oNsMNGZCYdDsVtRHSak0pcV5Dno5+4jh9sw==}
    engines: {node: '>=0.4.0'}
    hasBin: true

+  ajv@6.14.0:
+    resolution: {integrity: sha512-IWrosm/yrn43eiKqkfkHis7QioDleaXQHdDVPKg0FSwwd/DuvyX79TZnFOnYpB7dcsFAMmtFztZuXPDvSePkFw==}
+
  any-promise@1.3.0:
    resolution: {integrity: sha512-7UvmKalWRt1wgjL1RrGxoSJW/0QZFIegpeGvZG9kjp8vrRu55XTHbwnqq2GpXm9uLbcuhxm3IqX9OB4MZR1b2A==}

+  balanced-match@4.0.4:
+    resolution: {integrity: sha512-BLrgEcRTwX2o6gGxGOCNyMvGSp35YofuYzw9h1IMTRmKqttAZZVU67bdb9Pr2vUHA8+j3i2tJfjO6C6+4myGTA==}
+    engines: {node: 18 || 20 || >=22}
+
+  brace-expansion@5.0.4:
+    resolution: {integrity: sha512-h+DEnpVvxmfVefa4jFbCf5HdH5YMDXRsmKflpf1pILZWRFlTbJpxeU55nJl4Smt5HQaGzg1o6RHFPJaOqnmBDg==}
+    engines: {node: 18 || 20 || >=22}
+
  bundle-require@5.1.0:
    resolution: {integrity: sha512-3WrrOuZiyaaZPWiEt4G3+IffISVC9HYlWueJEBWED4ZH4aIAC2PnkdnuRrR94M+w6yGWn4AglWtJtBI8YqvgoA==}
    engines: {node: ^12.20.0 || ^14.13.1 || >=16.0.0}
@ -366,6 +517,10 @@ packages:
    resolution: {integrity: sha512-5IKcdX0nnYavi6G7TtOhwkYzyjfJlatbjMjuLSfE2kYT5pMDOilZ4OvMhi637CcDICTmz3wARPoyhqyX1Y+XvA==}
    engines: {node: ^14.18.0 || >=16.10.0}

+  cross-spawn@7.0.6:
+    resolution: {integrity: sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==}
+    engines: {node: '>= 8'}
+
  debug@4.4.3:
    resolution: {integrity: sha512-RGwwWnwQvkVfavKVt22FGLw+xYSdzARwm0ru6DhTVA3umU5hZc28V3kO4stgYryrTlLpuvgI9GiijltAjNbcqA==}
    engines: {node: '>=6.0'}
@ -375,11 +530,75 @@ packages:
      supports-color:
        optional: true

+  deep-is@0.1.4:
+    resolution: {integrity: sha512-oIPzksmTg4/MriiaYGO+okXDT7ztn/w3Eptv/+gSIdMdKsJo0u4CfYNFJPy+4SKMuCqGw2wxnA+URMg3t8a/bQ==}
+
  esbuild@0.27.3:
    resolution: {integrity: sha512-8VwMnyGCONIs6cWue2IdpHxHnAjzxnw2Zr7MkVxB2vjmQ2ivqGFb4LEG3SMnv0Gb2F/G/2yA8zUaiL1gywDCCg==}
    engines: {node: '>=18'}
    hasBin: true

+  escape-string-regexp@4.0.0:
+    resolution: {integrity: sha512-TtpcNJ3XAzx3Gq8sWRzJaVajRs0uVxA2YAkdb1jm2YkPz4G6egUFAyA3n5vtEIZefPk5Wa4UXbKuS5fKkJWdgA==}
+    engines: {node: '>=10'}
+
+  eslint-config-prettier@10.1.8:
+    resolution: {integrity: sha512-82GZUjRS0p/jganf6q1rEO25VSoHH0hKPCTrgillPjdI/3bgBhAE1QzHrHTizjpRvy6pGAvKjDJtk2pF9NDq8w==}
+    hasBin: true
+    peerDependencies:
+      eslint: '>=7.0.0'
+
+  eslint-scope@9.1.2:
+    resolution: {integrity: sha512-xS90H51cKw0jltxmvmHy2Iai1LIqrfbw57b79w/J7MfvDfkIkFZ+kj6zC3BjtUwh150HsSSdxXZcsuv72miDFQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  eslint-visitor-keys@3.4.3:
+    resolution: {integrity: sha512-wpc+LXeiyiisxPlEkUzU6svyS1frIO3Mgxj1fdy7Pm8Ygzguax2N3Fa/D/ag1WqbOprdI+uY6wMUl8/a2G+iag==}
+    engines: {node: ^12.22.0 || ^14.17.0 || >=16.0.0}
+
+  eslint-visitor-keys@5.0.1:
+    resolution: {integrity: sha512-tD40eHxA35h0PEIZNeIjkHoDR4YjjJp34biM0mDvplBe//mB+IHCqHDGV7pxF+7MklTvighcCPPZC7ynWyjdTA==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  eslint@10.0.3:
+    resolution: {integrity: sha512-COV33RzXZkqhG9P2rZCFl9ZmJ7WL+gQSCRzE7RhkbclbQPtLAWReL7ysA0Sh4c8Im2U9ynybdR56PV0XcKvqaQ==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+    hasBin: true
+    peerDependencies:
+      jiti: '*'
+    peerDependenciesMeta:
+      jiti:
+        optional: true
+
+  espree@11.2.0:
+    resolution: {integrity: sha512-7p3DrVEIopW1B1avAGLuCSh1jubc01H2JHc8B4qqGblmg5gI9yumBgACjWo4JlIc04ufug4xJ3SQI8HkS/Rgzw==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+
+  esquery@1.7.0:
+    resolution: {integrity: sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==}
+    engines: {node: '>=0.10'}
+
+  esrecurse@4.3.0:
+    resolution: {integrity: sha512-KmfKL3b6G+RXvP8N1vr3Tq1kL/oCFgn2NYXEtqP8/L3pKapUA4G8cFVaoF3SU323CD4XypR/ffioHmkti6/Tag==}
+    engines: {node: '>=4.0'}
+
+  estraverse@5.3.0:
+    resolution: {integrity: sha512-MMdARuVEQziNTeJD8DgMqmhwR11BRQ/cBP+pLtYdSTnf3MIO8fFeiINEbX36ZdNlfU/7A9f3gUw49B3oQsvwBA==}
+    engines: {node: '>=4.0'}
+
+  esutils@2.0.3:
+    resolution: {integrity: sha512-kVscqXk4OCp68SZ0dkgEKVi6/8ij300KBWTJq32P/dYeWTSwK41WyTxalN1eRmA5Z9UU/LX9D7FWSmV9SAYx6g==}
+    engines: {node: '>=0.10.0'}
+
+  fast-deep-equal@3.1.3:
+    resolution: {integrity: sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==}
+
+  fast-json-stable-stringify@2.1.0:
+    resolution: {integrity: sha512-lhd/wF+Lk98HZoTCtlVraHtfh5XYijIjalXck7saUtuanSDyLMxnHhSXEDJqHxD7msR8D0uCmqlkwjCV8xvwHw==}
+
+  fast-levenshtein@2.0.6:
+    resolution: {integrity: sha512-DCXu6Ifhqcks7TZKY3Hxp3y6qphY5SJZmrWMDrKcERSOXWQdMhU9Ig/PYrzyw/ul9jOIyh0N4M0tbC5hodg8dw==}
+
  fdir@6.5.0:
    resolution: {integrity: sha512-tIbYtZbucOs0BRGqPJkshJUYdL+SDH7dVM8gjy+ERp3WAUjLEFJE+02kanyHtwjWOnwrKYBiwAmM0p4kLJAnXg==}
    engines: {node: '>=12.0.0'}
@ -389,18 +608,76 @@ packages:
      picomatch:
        optional: true

+  file-entry-cache@8.0.0:
+    resolution: {integrity: sha512-XXTUwCvisa5oacNGRP9SfNtYBNAMi+RPwBFmblZEF7N7swHYQS6/Zfk7SRwx4D5j3CH211YNRco1DEMNVfZCnQ==}
+    engines: {node: '>=16.0.0'}
+
+  find-up@5.0.0:
+    resolution: {integrity: sha512-78/PXT1wlLLDgTzDs7sjq9hzz0vXD+zn+7wypEe4fXQxCmdmqfGsEPQxmiCSQI3ajFV91bVSsvNtrJRiW6nGng==}
+    engines: {node: '>=10'}
+
  fix-dts-default-cjs-exports@1.0.1:
    resolution: {integrity: sha512-pVIECanWFC61Hzl2+oOCtoJ3F17kglZC/6N94eRWycFgBH35hHx0Li604ZIzhseh97mf2p0cv7vVrOZGoqhlEg==}

+  flat-cache@4.0.1:
+    resolution: {integrity: sha512-f7ccFPK3SXFHpx15UIGyRJ/FJQctuKZ0zVuN3frBo4HnK3cay9VEW0R6yPYFHC0AgqhukPzKjq22t5DmAyqGyw==}
+    engines: {node: '>=16'}
+
+  flatted@3.3.4:
+    resolution: {integrity: sha512-3+mMldrTAPdta5kjX2G2J7iX4zxtnwpdA8Tr2ZSjkyPSanvbZAcy6flmtnXbEybHrDcU9641lxrMfFuUxVz9vA==}
+
  fsevents@2.3.3:
    resolution: {integrity: sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==}
    engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
    os: [darwin]

+  glob-parent@6.0.2:
+    resolution: {integrity: sha512-XxwI8EOhVQgWp6iDL+3b0r86f4d6AX6zSU55HfB4ydCEuXLXc5FcYeOu+nnGftS4TEju/11rt4KJPTMgbfmv4A==}
+    engines: {node: '>=10.13.0'}
+
+  ignore@5.3.2:
+    resolution: {integrity: sha512-hsBTNUqQTDwkWtcdYI2i06Y/nUBEsNEDJKjWdigLvegy8kDuJAS8uRlpkkcQpyEXL0Z/pjDy5HBmMjRCJ2gq+g==}
+    engines: {node: '>= 4'}
+
+  ignore@7.0.5:
+    resolution: {integrity: sha512-Hs59xBNfUIunMFgWAbGX5cq6893IbWg4KnrjbYwX3tx0ztorVgTDA6B2sxf8ejHJ4wz8BqGUMYlnzNBer5NvGg==}
+    engines: {node: '>= 4'}
+
+  imurmurhash@0.1.4:
+    resolution: {integrity: sha512-JmXMZ6wuvDmLiHEml9ykzqO6lwFbof0GG4IkcGaENdCRDDmMVnny7s5HsIgHCbaq0w2MyPhDqkhTUgS2LU2PHA==}
+    engines: {node: '>=0.8.19'}
+
+  is-extglob@2.1.1:
+    resolution: {integrity: sha512-SbKbANkN603Vi4jEZv49LeVJMn4yGwsbzZworEoyEiutsN3nJYdbO36zfhGJ6QEDpOZIFkDtnq5JRxmvl3jsoQ==}
+    engines: {node: '>=0.10.0'}
+
+  is-glob@4.0.3:
+    resolution: {integrity: sha512-xelSayHH36ZgE7ZWhli7pW34hNbNl8Ojv5KVmkJD4hBdD3th8Tfk9vYasLM+mXWOZhFkgZfxhLSnrwRr4elSSg==}
+    engines: {node: '>=0.10.0'}
+
+  isexe@2.0.0:
+    resolution: {integrity: sha512-RHxMLp9lnKHGHRng9QFhRCMbYAcVpn69smSGcq3f36xjgVVWThj4qqLbTLlq7Ssj8B+fIQ1EuCEGI2lKsyQeIw==}
+
  joycon@3.1.1:
    resolution: {integrity: sha512-34wB/Y7MW7bzjKRjUKTa46I2Z7eV62Rkhva+KkopW7Qvv/OSWBqvkSY7vusOPrNuZcUG3tApvdVgNB8POj3SPw==}
    engines: {node: '>=10'}

+  json-buffer@3.0.1:
+    resolution: {integrity: sha512-4bV5BfR2mqfQTJm+V5tPPdf+ZpuhiIvTuAB5g8kcrXOZpTT/QwwVRWBywX1ozr6lEuPdbHxwaJlm9G6mI2sfSQ==}
+
+  json-schema-traverse@0.4.1:
+    resolution: {integrity: sha512-xbbCH5dCYU5T8LcEhhuh7HJ88HXuW3qsI3Y0zOZFKfZEHcpWiHU/Jxzk629Brsab/mMiHQti9wMP+845RPe3Vg==}
+
+  json-stable-stringify-without-jsonify@1.0.1:
+    resolution: {integrity: sha512-Bdboy+l7tA3OGW6FjyFHWkP5LuByj1Tk33Ljyq0axyzdk9//JSi2u3fP1QSmd1KNwq6VOKYGlAu87CisVir6Pw==}
+
+  keyv@4.5.4:
+    resolution: {integrity: sha512-oxVHkHR/EJf2CNXnWxRLW6mg7JyCCUcG0DtEGmL2ctUo1PNTin1PUil+r/+4r5MpVgC/fn1kjsx7mjSujKqIpw==}
+
+  levn@0.4.1:
+    resolution: {integrity: sha512-+bT2uH4E5LGE7h/n3evcS/sQlJXCpIp6ym8OWJ5eV6+67Dsql/LaaT7qJBAt2rzfoa/5QBGBhxDix1dMt2kQKQ==}
+    engines: {node: '>= 0.8.0'}
+
  lilconfig@3.1.3:
    resolution: {integrity: sha512-/vlFKAoH5Cgt3Ie+JLhRbwOsCQePABiU3tJ1egGvyQ+33R/vcwM2Zl2QR/LzjsBeItPt3oSVXapn+m4nQDvpzw==}
    engines: {node: '>=14'}
@ -412,9 +689,17 @@ packages:
    resolution: {integrity: sha512-IXO6OCs9yg8tMKzfPZ1YmheJbZCiEsnBdcB03l0OcfK9prKnJb96siuHCr5Fl37/yo9DnKU+TLpxzTUspw9shg==}
    engines: {node: ^12.20.0 || ^14.13.1 || >=16.0.0}

+  locate-path@6.0.0:
+    resolution: {integrity: sha512-iPZK6eYjbxRu3uB4/WZ3EsEIMJFMqAoopl3R+zuq0UjcAm/MO6KCweDgPfP3elTztoKP3KtnVHxTn2NHBSDVUw==}
+    engines: {node: '>=10'}
+
  magic-string@0.30.21:
    resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}

+  minimatch@10.2.4:
+    resolution: {integrity: sha512-oRjTw/97aTBN0RHbYCdtF1MQfvusSIBQM0IZEgzl6426+8jSC0nF1a/GmnVLpfB9yyr6g6FTqWqiZVbxrtaCIg==}
+    engines: {node: 18 || 20 || >=22}
+
  mlly@1.8.0:
    resolution: {integrity: sha512-l8D9ODSRWLe2KHJSifWGwBqpTZXIXTeo8mlKjY+E2HAakaTeNpqAyBZ8GSqLzHgw4XmHmC8whvpjJNMbFZN7/g==}

@ -424,10 +709,33 @@ packages:
  mz@2.7.0:
    resolution: {integrity: sha512-z81GNO7nnYMEhrGh9LeymoE4+Yr0Wn5McHIZMK5cfQCl+NDX08sCZgUc9/6MHni9IWuFLm1Z3HTCXu2z9fN62Q==}

+  natural-compare@1.4.0:
+    resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
+
  object-assign@4.1.1:
    resolution: {integrity: sha512-rJgTQnkUnH1sFw8yT6VSU3zD3sWmu6sZhIseY8VX+GRu3P6F7Fu+JNDoXfklElbLJSnc3FUQHVe4cU5hj+BcUg==}
    engines: {node: '>=0.10.0'}

+  optionator@0.9.4:
+    resolution: {integrity: sha512-6IpQ7mKUxRcZNLIObR0hz7lxsapSSIYNZJwXPGeF0mTVqGKFIXj1DQcMoT22S3ROcLyY/rz0PWaWZ9ayWmad9g==}
+    engines: {node: '>= 0.8.0'}
+
+  p-limit@3.1.0:
+    resolution: {integrity: sha512-TYOanM3wGwNGsZN2cVTYPArw454xnXj5qmWF1bEoAc4+cU/ol7GVh7odevjp1FNHduHc3KZMcFduxU5Xc6uJRQ==}
+    engines: {node: '>=10'}
+
+  p-locate@5.0.0:
+    resolution: {integrity: sha512-LaNjtRWUBY++zB5nE/NwcaoMylSPk+S+ZHNB1TzdbMJMny6dynpAGt7X/tl/QYq3TIeE6nxHppbo2LGymrG5Pw==}
+    engines: {node: '>=10'}
+
+  path-exists@4.0.0:
+    resolution: {integrity: sha512-ak9Qy5Q7jYb2Wwcey5Fpvg2KoAc/ZIhLSLOSBmRmygPsGwkVVt0fZa0qrtMz+m6tJTAHfZQ8FnmB4MG4LWy7/w==}
+    engines: {node: '>=8'}
+
+  path-key@3.1.1:
+    resolution: {integrity: sha512-ojmeN0qd+y0jszEtoY48r0Peq5dwMEkIlCOu6Q5f41lfkswXuKtYrhgoTpLnyIcHm24Uhqx+5Tqm2InSwLhE6Q==}
+    engines: {node: '>=8'}
+
  pathe@2.0.3:
    resolution: {integrity: sha512-WUjGcAqP1gQacoQe+OBJsFA7Ld4DyXuUIjZ5cc75cLHvJ7dtNsTugphxIADwspS+AraAUePCKrSVtPLFj/F88w==}

@ -463,6 +771,19 @@ packages:
      yaml:
        optional: true

+  prelude-ls@1.2.1:
+    resolution: {integrity: sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==}
+    engines: {node: '>= 0.8.0'}
+
+  prettier@3.8.1:
+    resolution: {integrity: sha512-UOnG6LftzbdaHZcKoPFtOcCKztrQ57WkHDeRD9t/PTQtmT0NHSeWWepj6pS0z/N7+08BHFDQVUrfmfMRcZwbMg==}
+    engines: {node: '>=14'}
+    hasBin: true
+
+  punycode@2.3.1:
+    resolution: {integrity: sha512-vYt7UD1U9Wg6138shLtLOvdAu+8DsC/ilFtEVHcH+wydcSpNE20AfSOduf6MkRFahL5FY7X1oU7nKVZFtfq8Fg==}
+    engines: {node: '>=6'}
+
  readdirp@4.1.2:
    resolution: {integrity: sha512-GDhwkLfywWL2s6vEjyhri+eXmfH6j1L7JE27WhqLeYzoh/A3DBaYGEj2H/HFZCn/kMfim73FXxEJTw06WtxQwg==}
    engines: {node: '>= 14.18.0'}
@ -476,6 +797,19 @@ packages:
    engines: {node: '>=18.0.0', npm: '>=8.0.0'}
    hasBin: true

+  semver@7.7.4:
+    resolution: {integrity: sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA==}
+    engines: {node: '>=10'}
+    hasBin: true
+
+  shebang-command@2.0.0:
+    resolution: {integrity: sha512-kHxr2zZpYtdmrN1qDjrrX/Z1rR1kG8Dx+gkpK1G4eXmvXswmcE1hTWBWYUzlraYw1/yZp6YuDY77YtvbN0dmDA==}
+    engines: {node: '>=8'}
+
+  shebang-regex@3.0.0:
+    resolution: {integrity: sha512-7++dFhtcx3353uBaq8DDR4NuxBetBzC7ZQOhmTQInHEd6bSrXdiEyzCvG07Z44UYdLShWUyXt5M/yhz8ekcb1A==}
+    engines: {node: '>=8'}
+
  source-map@0.7.6:
    resolution: {integrity: sha512-i5uvt8C3ikiWeNZSVZNWcfZPItFQOsYTUAOkcUPGd8DqDy1uOUikjt5dG+uRlwyvR108Fb9DOd4GvXfT0N2/uQ==}
    engines: {node: '>= 12'}
@ -503,6 +837,12 @@ packages:
    resolution: {integrity: sha512-L0Orpi8qGpRG//Nd+H90vFB+3iHnue1zSSGmNOOCh1GLJ7rUKVwV2HvijphGQS2UmhUZewS9VgvxYIdgr+fG1A==}
    hasBin: true

+  ts-api-utils@2.4.0:
+    resolution: {integrity: sha512-3TaVTaAv2gTiMB35i3FiGJaRfwb3Pyn/j3m/bfAvGe8FB7CF6u+LMYqYlDh7reQf7UNvoTvdfAqHGmPGOSsPmA==}
+    engines: {node: '>=18.12'}
+    peerDependencies:
+      typescript: '>=4.8.4'
+
  ts-interface-checker@0.1.13:
    resolution: {integrity: sha512-Y/arvbn+rrz3JCKl9C4kVNfTfSm2/mEp5FSz5EsZSANGPSlQrpRI5M4PKF+mJnE52jOO90PnPSc3Ur3bTQw0gA==}

@ -525,6 +865,17 @@ packages:
      typescript:
        optional: true

+  type-check@0.4.0:
+    resolution: {integrity: sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==}
+    engines: {node: '>= 0.8.0'}
+
+  typescript-eslint@8.56.1:
+    resolution: {integrity: sha512-U4lM6pjmBX7J5wk4szltF7I1cGBHXZopnAXCMXb3+fZ3B/0Z3hq3wS/CCUB2NZBNAExK92mCU2tEohWuwVMsDQ==}
+    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+    peerDependencies:
+      eslint: ^8.57.0 || ^9.0.0 || ^10.0.0
+      typescript: '>=4.8.4 <6.0.0'
+
  typescript@5.9.3:
    resolution: {integrity: sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==}
    engines: {node: '>=14.17'}
@ -536,6 +887,22 @@ packages:
  undici-types@6.21.0:
    resolution: {integrity: sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ==}

+  uri-js@4.4.1:
+    resolution: {integrity: sha512-7rKUyy33Q1yc98pQ1DAmLtwX109F7TIfWlW1Ydo8Wl1ii1SeHieeh0HHfPeL2fMXK6z0s8ecKs9frCuLJvndBg==}
+
+  which@2.0.2:
+    resolution: {integrity: sha512-BLI3Tl1TW3Pvl70l3yq3Y64i+awpwXqsGBYWkkqMtnbXgrMD+yj7rhW0kuEDxzJaYXGjEW5ogapKNMEKNMjibA==}
+    engines: {node: '>= 8'}
+    hasBin: true
+
+  word-wrap@1.2.5:
+    resolution: {integrity: sha512-BN22B5eaMMI9UMtjrGd5g5eCYPpCPDUy0FJXbYsaT5zYxjFOckS53SQDE3pWkVoWpHXVb3BrYcEN4Twa55B5cA==}
+    engines: {node: '>=0.10.0'}
+
+  yocto-queue@0.1.0:
+    resolution: {integrity: sha512-rVksvsnNCdJ/ohGc6xgPwyN8eheCxsiLM8mxuE/t/mOVqJewPuO1miLpTHQiRgTKCLexL4MeAFVagts7HmNZ2Q==}
+    engines: {node: '>=10'}
+
 snapshots:

  '@esbuild/aix-ppc64@0.27.3':
@ -616,6 +983,51 @@ snapshots:
  '@esbuild/win32-x64@0.27.3':
    optional: true

+  '@eslint-community/eslint-utils@4.9.1(eslint@10.0.3)':
+    dependencies:
+      eslint: 10.0.3
+      eslint-visitor-keys: 3.4.3
+
+  '@eslint-community/regexpp@4.12.2': {}
+
+  '@eslint/config-array@0.23.3':
+    dependencies:
+      '@eslint/object-schema': 3.0.3
+      debug: 4.4.3
+      minimatch: 10.2.4
+    transitivePeerDependencies:
+      - supports-color
+
+  '@eslint/config-helpers@0.5.3':
+    dependencies:
+      '@eslint/core': 1.1.1
+
+  '@eslint/core@1.1.1':
+    dependencies:
+      '@types/json-schema': 7.0.15
+
+  '@eslint/js@10.0.1(eslint@10.0.3)':
+    optionalDependencies:
+      eslint: 10.0.3
+
+  '@eslint/object-schema@3.0.3': {}
+
+  '@eslint/plugin-kit@0.6.1':
+    dependencies:
+      '@eslint/core': 1.1.1
+      levn: 0.4.1
+
+  '@humanfs/core@0.19.1': {}
+
+  '@humanfs/node@0.16.7':
+    dependencies:
+      '@humanfs/core': 0.19.1
+      '@humanwhocodes/retry': 0.4.3
+
+  '@humanwhocodes/module-importer@1.0.1': {}
+
+  '@humanwhocodes/retry@0.4.3': {}
+
  '@jridgewell/gen-mapping@0.3.13':
    dependencies:
      '@jridgewell/sourcemap-codec': 1.5.5
@ -705,16 +1117,128 @@ snapshots:
  '@rollup/rollup-win32-x64-msvc@4.59.0':
    optional: true

+  '@types/esrecurse@4.3.1': {}
+
  '@types/estree@1.0.8': {}

+  '@types/json-schema@7.0.15': {}
+
  '@types/node@22.19.11':
    dependencies:
      undici-types: 6.21.0

+  '@typescript-eslint/eslint-plugin@8.56.1(@typescript-eslint/parser@8.56.1(eslint@10.0.3)(typescript@5.9.3))(eslint@10.0.3)(typescript@5.9.3)':
+    dependencies:
+      '@eslint-community/regexpp': 4.12.2
+      '@typescript-eslint/parser': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      '@typescript-eslint/scope-manager': 8.56.1
+      '@typescript-eslint/type-utils': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      '@typescript-eslint/visitor-keys': 8.56.1
+      eslint: 10.0.3
+      ignore: 7.0.5
+      natural-compare: 1.4.0
+      ts-api-utils: 2.4.0(typescript@5.9.3)
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/parser@8.56.1(eslint@10.0.3)(typescript@5.9.3)':
+    dependencies:
+      '@typescript-eslint/scope-manager': 8.56.1
+      '@typescript-eslint/types': 8.56.1
+      '@typescript-eslint/typescript-estree': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/visitor-keys': 8.56.1
+      debug: 4.4.3
+      eslint: 10.0.3
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/project-service@8.56.1(typescript@5.9.3)':
+    dependencies:
+      '@typescript-eslint/tsconfig-utils': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/types': 8.56.1
+      debug: 4.4.3
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/scope-manager@8.56.1':
+    dependencies:
+      '@typescript-eslint/types': 8.56.1
+      '@typescript-eslint/visitor-keys': 8.56.1
+
+  '@typescript-eslint/tsconfig-utils@8.56.1(typescript@5.9.3)':
+    dependencies:
+      typescript: 5.9.3
+
+  '@typescript-eslint/type-utils@8.56.1(eslint@10.0.3)(typescript@5.9.3)':
+    dependencies:
+      '@typescript-eslint/types': 8.56.1
+      '@typescript-eslint/typescript-estree': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      debug: 4.4.3
+      eslint: 10.0.3
+      ts-api-utils: 2.4.0(typescript@5.9.3)
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/types@8.56.1': {}
+
+  '@typescript-eslint/typescript-estree@8.56.1(typescript@5.9.3)':
+    dependencies:
+      '@typescript-eslint/project-service': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/tsconfig-utils': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/types': 8.56.1
+      '@typescript-eslint/visitor-keys': 8.56.1
+      debug: 4.4.3
+      minimatch: 10.2.4
+      semver: 7.7.4
+      tinyglobby: 0.2.15
+      ts-api-utils: 2.4.0(typescript@5.9.3)
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/utils@8.56.1(eslint@10.0.3)(typescript@5.9.3)':
+    dependencies:
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.3)
+      '@typescript-eslint/scope-manager': 8.56.1
+      '@typescript-eslint/types': 8.56.1
+      '@typescript-eslint/typescript-estree': 8.56.1(typescript@5.9.3)
+      eslint: 10.0.3
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
+  '@typescript-eslint/visitor-keys@8.56.1':
+    dependencies:
+      '@typescript-eslint/types': 8.56.1
+      eslint-visitor-keys: 5.0.1
+
+  acorn-jsx@5.3.2(acorn@8.16.0):
+    dependencies:
+      acorn: 8.16.0
+
  acorn@8.16.0: {}

+  ajv@6.14.0:
+    dependencies:
+      fast-deep-equal: 3.1.3
+      fast-json-stable-stringify: 2.1.0
+      json-schema-traverse: 0.4.1
+      uri-js: 4.4.1
+
  any-promise@1.3.0: {}

+  balanced-match@4.0.4: {}
+
+  brace-expansion@5.0.4:
+    dependencies:
+      balanced-match: 4.0.4
+
  bundle-require@5.1.0(esbuild@0.27.3):
    dependencies:
      esbuild: 0.27.3
@ -732,10 +1256,18 @@ snapshots:

  consola@3.4.2: {}

+  cross-spawn@7.0.6:
+    dependencies:
+      path-key: 3.1.1
+      shebang-command: 2.0.0
+      which: 2.0.2
+
  debug@4.4.3:
    dependencies:
      ms: 2.1.3

+  deep-is@0.1.4: {}
+
  esbuild@0.27.3:
    optionalDependencies:
      '@esbuild/aix-ppc64': 0.27.3
@ -765,31 +1297,164 @@ snapshots:
      '@esbuild/win32-ia32': 0.27.3
      '@esbuild/win32-x64': 0.27.3

+  escape-string-regexp@4.0.0: {}
+
+  eslint-config-prettier@10.1.8(eslint@10.0.3):
+    dependencies:
+      eslint: 10.0.3
+
+  eslint-scope@9.1.2:
+    dependencies:
+      '@types/esrecurse': 4.3.1
+      '@types/estree': 1.0.8
+      esrecurse: 4.3.0
+      estraverse: 5.3.0
+
+  eslint-visitor-keys@3.4.3: {}
+
+  eslint-visitor-keys@5.0.1: {}
+
+  eslint@10.0.3:
+    dependencies:
+      '@eslint-community/eslint-utils': 4.9.1(eslint@10.0.3)
+      '@eslint-community/regexpp': 4.12.2
+      '@eslint/config-array': 0.23.3
+      '@eslint/config-helpers': 0.5.3
+      '@eslint/core': 1.1.1
+      '@eslint/plugin-kit': 0.6.1
+      '@humanfs/node': 0.16.7
+      '@humanwhocodes/module-importer': 1.0.1
+      '@humanwhocodes/retry': 0.4.3
+      '@types/estree': 1.0.8
+      ajv: 6.14.0
+      cross-spawn: 7.0.6
+      debug: 4.4.3
+      escape-string-regexp: 4.0.0
+      eslint-scope: 9.1.2
+      eslint-visitor-keys: 5.0.1
+      espree: 11.2.0
+      esquery: 1.7.0
+      esutils: 2.0.3
+      fast-deep-equal: 3.1.3
+      file-entry-cache: 8.0.0
+      find-up: 5.0.0
+      glob-parent: 6.0.2
+      ignore: 5.3.2
+      imurmurhash: 0.1.4
+      is-glob: 4.0.3
+      json-stable-stringify-without-jsonify: 1.0.1
+      minimatch: 10.2.4
+      natural-compare: 1.4.0
+      optionator: 0.9.4
+    transitivePeerDependencies:
+      - supports-color
+
+  espree@11.2.0:
+    dependencies:
+      acorn: 8.16.0
+      acorn-jsx: 5.3.2(acorn@8.16.0)
+      eslint-visitor-keys: 5.0.1
+
+  esquery@1.7.0:
+    dependencies:
+      estraverse: 5.3.0
+
+  esrecurse@4.3.0:
+    dependencies:
+      estraverse: 5.3.0
+
+  estraverse@5.3.0: {}
+
+  esutils@2.0.3: {}
+
+  fast-deep-equal@3.1.3: {}
+
+  fast-json-stable-stringify@2.1.0: {}
+
+  fast-levenshtein@2.0.6: {}
+
  fdir@6.5.0(picomatch@4.0.3):
    optionalDependencies:
      picomatch: 4.0.3

+  file-entry-cache@8.0.0:
+    dependencies:
+      flat-cache: 4.0.1
+
+  find-up@5.0.0:
+    dependencies:
+      locate-path: 6.0.0
+      path-exists: 4.0.0
+
  fix-dts-default-cjs-exports@1.0.1:
    dependencies:
      magic-string: 0.30.21
      mlly: 1.8.0
      rollup: 4.59.0

+  flat-cache@4.0.1:
+    dependencies:
+      flatted: 3.3.4
+      keyv: 4.5.4
+
+  flatted@3.3.4: {}
+
  fsevents@2.3.3:
    optional: true

+  glob-parent@6.0.2:
+    dependencies:
+      is-glob: 4.0.3
+
+  ignore@5.3.2: {}
+
+  ignore@7.0.5: {}
+
+  imurmurhash@0.1.4: {}
+
+  is-extglob@2.1.1: {}
+
+  is-glob@4.0.3:
+    dependencies:
+      is-extglob: 2.1.1
+
+  isexe@2.0.0: {}
+
  joycon@3.1.1: {}

+  json-buffer@3.0.1: {}
+
+  json-schema-traverse@0.4.1: {}
+
+  json-stable-stringify-without-jsonify@1.0.1: {}
+
+  keyv@4.5.4:
+    dependencies:
+      json-buffer: 3.0.1
+
+  levn@0.4.1:
+    dependencies:
+      prelude-ls: 1.2.1
+      type-check: 0.4.0
+
  lilconfig@3.1.3: {}

  lines-and-columns@1.2.4: {}

  load-tsconfig@0.2.5: {}

+  locate-path@6.0.0:
+    dependencies:
+      p-locate: 5.0.0
+
  magic-string@0.30.21:
    dependencies:
      '@jridgewell/sourcemap-codec': 1.5.5

+  minimatch@10.2.4:
+    dependencies:
+      brace-expansion: 5.0.4
+
  mlly@1.8.0:
    dependencies:
      acorn: 8.16.0
@ -805,8 +1470,31 @@ snapshots:
      object-assign: 4.1.1
      thenify-all: 1.6.0

+  natural-compare@1.4.0: {}
+
  object-assign@4.1.1: {}

+  optionator@0.9.4:
+    dependencies:
+      deep-is: 0.1.4
+      fast-levenshtein: 2.0.6
+      levn: 0.4.1
+      prelude-ls: 1.2.1
+      type-check: 0.4.0
+      word-wrap: 1.2.5
+
+  p-limit@3.1.0:
+    dependencies:
+      yocto-queue: 0.1.0
+
+  p-locate@5.0.0:
+    dependencies:
+      p-limit: 3.1.0
+
+  path-exists@4.0.0: {}
+
+  path-key@3.1.1: {}
+
  pathe@2.0.3: {}

  picocolors@1.1.1: {}
@ -825,6 +1513,12 @@ snapshots:
    dependencies:
      lilconfig: 3.1.3

+  prelude-ls@1.2.1: {}
+
+  prettier@3.8.1: {}
+
+  punycode@2.3.1: {}
+
  readdirp@4.1.2: {}

  resolve-from@5.0.0: {}
@ -860,6 +1554,14 @@ snapshots:
      '@rollup/rollup-win32-x64-msvc': 4.59.0
      fsevents: 2.3.3

+  semver@7.7.4: {}
+
+  shebang-command@2.0.0:
+    dependencies:
+      shebang-regex: 3.0.0
+
+  shebang-regex@3.0.0: {}
+
  source-map@0.7.6: {}

  sucrase@3.35.1:
@ -889,6 +1591,10 @@ snapshots:

  tree-kill@1.2.2: {}

+  ts-api-utils@2.4.0(typescript@5.9.3):
+    dependencies:
+      typescript: 5.9.3
+
  ts-interface-checker@0.1.13: {}

  tsup@8.5.1(typescript@5.9.3):
@ -918,8 +1624,35 @@ snapshots:
      - tsx
      - yaml

+  type-check@0.4.0:
+    dependencies:
+      prelude-ls: 1.2.1
+
+  typescript-eslint@8.56.1(eslint@10.0.3)(typescript@5.9.3):
+    dependencies:
+      '@typescript-eslint/eslint-plugin': 8.56.1(@typescript-eslint/parser@8.56.1(eslint@10.0.3)(typescript@5.9.3))(eslint@10.0.3)(typescript@5.9.3)
+      '@typescript-eslint/parser': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      '@typescript-eslint/typescript-estree': 8.56.1(typescript@5.9.3)
+      '@typescript-eslint/utils': 8.56.1(eslint@10.0.3)(typescript@5.9.3)
+      eslint: 10.0.3
+      typescript: 5.9.3
+    transitivePeerDependencies:
+      - supports-color
+
  typescript@5.9.3: {}

  ufo@1.6.3: {}

  undici-types@6.21.0: {}
+
+  uri-js@4.4.1:
+    dependencies:
+      punycode: 2.3.1
+
+  which@2.0.2:
+    dependencies:
+      isexe: 2.0.0
+
+  word-wrap@1.2.5: {}
+
+  yocto-queue@0.1.0: {}
--- a/src/cycleMonth.ts
+++ b/src/cycleMonth.ts
@ -14,6 +14,10 @@ const SYNODIC_SECONDS = SYNODIC_MONTH * 24 * 60 * 60;
 * @returns A zero-padded filename string, e.g. `"354.webp"`.
 */
 export function cycleMonth(date: Date = new Date()): string {
+  if (!(date instanceof Date) || isNaN(date.getTime())) {
+    throw new TypeError('date must be a valid Date instance');
+  }
+
  // Seconds elapsed since the known new moon anchor
  const elapsed = (date.getTime() - MONTH_ANCHOR.getTime()) / 1000;

--- a/src/cycleYear.ts
+++ b/src/cycleYear.ts
@ -15,6 +15,10 @@ import { YEAR_IMAGES, YEAR_ANCHOR } from './types.js';
 * @returns A zero-padded filename string, e.g. `"4380.webp"`.
 */
 export function cycleYear(date: Date = new Date()): string {
+  if (!(date instanceof Date) || isNaN(date.getTime())) {
+    throw new TypeError('date must be a valid Date instance');
+  }
+
  // Hours elapsed since 2023-01-01T00:00:00Z
  const elapsed_hours = (date.getTime() - YEAR_ANCHOR.getTime()) / (1000 * 3600);

--- a/src/helpers.ts
+++ b/src/helpers.ts
@ -38,7 +38,7 @@ export function cdnUrl(
  set: ImageSet,
  size: ImageSize,
  quality: ImageQuality,
-  ref: string = 'main'
+  ref: string = 'main',
 ): string {
  const folder = imageFolder(set, size, quality);
  return `https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@${ref}/${folder}/${filename}`;
--- a/test-cjs.cjs
+++ b/test-cjs.cjs
@ -5,6 +5,7 @@

 'use strict';

+const { describe, it } = require('node:test');
 const assert = require('node:assert/strict');
 const {
  cycleMonth,
@ -18,62 +19,57 @@ const {
  YEAR_ANCHOR,
 } = require('./dist/index.cjs');

-let passed = 0;
-let total = 0;
+describe('CJS exports', () => {
+  it('all exports are available via require()', () => {
+    assert.strictEqual(typeof cycleMonth, 'function');
+    assert.strictEqual(typeof cycleYear, 'function');
+    assert.strictEqual(typeof imageFolder, 'function');
+    assert.strictEqual(typeof cdnUrl, 'function');
+    assert.strictEqual(typeof SYNODIC_MONTH, 'number');
+    assert.strictEqual(typeof MONTH_IMAGES, 'number');
+    assert.strictEqual(typeof YEAR_IMAGES, 'number');
+    assert(MONTH_ANCHOR instanceof Date);
+    assert(YEAR_ANCHOR instanceof Date);
+  });

-function test(name, fn) {
-  total++;
-  try {
-    fn();
-    console.log(`[${name}]... PASS`);
-    passed++;
-  } catch (err) {
-    console.error(`[${name}]... FAIL: ${err.message}`);
-    process.exitCode = 1;
-  }
-}
+  it('cycleMonth at anchor returns 001.webp', () => {
+    assert.strictEqual(cycleMonth(MONTH_ANCHOR), '001.webp');
+  });

-test('exports are available via require()', () => {
-  assert.strictEqual(typeof cycleMonth, 'function');
-  assert.strictEqual(typeof cycleYear, 'function');
-  assert.strictEqual(typeof imageFolder, 'function');
-  assert.strictEqual(typeof cdnUrl, 'function');
-  assert.strictEqual(typeof SYNODIC_MONTH, 'number');
-  assert.strictEqual(typeof MONTH_IMAGES, 'number');
-  assert.strictEqual(typeof YEAR_IMAGES, 'number');
-  assert(MONTH_ANCHOR instanceof Date);
-  assert(YEAR_ANCHOR instanceof Date);
+  it('cycleYear at anchor returns 0001.webp', () => {
+    assert.strictEqual(cycleYear(YEAR_ANCHOR), '0001.webp');
+  });
+
+  it('cycleMonth result format is correct', () => {
+    assert.match(cycleMonth(), /^\d{3}\.webp$/);
+  });
+
+  it('cycleYear result format is correct', () => {
+    assert.match(cycleYear(), /^\d{4}\.webp$/);
+  });
+
+  it('imageFolder constructs correct path', () => {
+    assert.strictEqual(imageFolder('mm', 256, 75), 'mm-256-75');
+  });
+
+  it('cdnUrl returns expected jsDelivr URL', () => {
+    assert.strictEqual(
+      cdnUrl('001.webp', 'mm', 256, 75),
+      'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/001.webp',
+    );
+  });
+
+  it('cycleMonth throws TypeError for invalid Date', () => {
+    assert.throws(() => cycleMonth(new Date('invalid')), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
+
+  it('cycleYear throws TypeError for invalid Date', () => {
+    assert.throws(() => cycleYear(new Date('invalid')), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
 });
-
-test('cycleMonth at anchor returns 001.webp', () => {
-  assert.strictEqual(cycleMonth(MONTH_ANCHOR), '001.webp');
-});
-
-test('cycleYear at anchor returns 0001.webp', () => {
-  assert.strictEqual(cycleYear(YEAR_ANCHOR), '0001.webp');
-});
-
-test('cycleMonth result format is correct', () => {
-  const result = cycleMonth();
-  assert.match(result, /^\d{3}\.webp$/);
-});
-
-test('cycleYear result format is correct', () => {
-  const result = cycleYear();
-  assert.match(result, /^\d{4}\.webp$/);
-});
-
-test('imageFolder constructs correct path', () => {
-  assert.strictEqual(imageFolder('mm', 256, 75), 'mm-256-75');
-});
-
-test('cdnUrl returns expected jsDelivr URL', () => {
-  const url = cdnUrl('001.webp', 'mm', 256, 75);
-  assert.strictEqual(
-    url,
-    'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/001.webp'
-  );
-});
-
-console.log(`\n${passed}/${total} tests passed`);
-if (passed < total) process.exit(1);
--- a/test.mjs
+++ b/test.mjs
@ -1,8 +1,9 @@
 /**
 * ESM test suite for moon-cycle v2.
- * Uses Node.js built-in assert — no test framework required.
+ * Uses Node.js built-in test runner.
 */

+import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import {
  cycleMonth,
@ -16,225 +17,211 @@ import {
  YEAR_ANCHOR,
 } from './dist/index.mjs';

-let passed = 0;
-let total = 0;
-
-function test(name, fn) {
-  total++;
-  try {
-    fn();
-    console.log(`[${name}]... PASS`);
-    passed++;
-  } catch (err) {
-    console.error(`[${name}]... FAIL: ${err.message}`);
-    process.exitCode = 1;
-  }
-}
-
 // ─── Constants ───────────────────────────────────────────────────────────────

-test('SYNODIC_MONTH is correct IAU value', () => {
-  assert.strictEqual(SYNODIC_MONTH, 29.53058821398858);
+describe('constants', () => {
+  it('SYNODIC_MONTH is correct IAU value', () => {
+    assert.strictEqual(SYNODIC_MONTH, 29.53058821398858);
+  });
+
+  it('MONTH_IMAGES is 708', () => {
+    assert.strictEqual(MONTH_IMAGES, 708);
+  });
+
+  it('YEAR_IMAGES is 8760', () => {
+    assert.strictEqual(YEAR_IMAGES, 8760);
+  });
+
+  it('MONTH_ANCHOR is 2023-11-13T09:27:00Z', () => {
+    assert.strictEqual(MONTH_ANCHOR.toISOString(), '2023-11-13T09:27:00.000Z');
+  });
+
+  it('YEAR_ANCHOR is 2023-01-01T00:00:00Z', () => {
+    assert.strictEqual(YEAR_ANCHOR.toISOString(), '2023-01-01T00:00:00.000Z');
+  });
 });

-test('MONTH_IMAGES is 708', () => {
-  assert.strictEqual(MONTH_IMAGES, 708);
-});
+// ─── cycleMonth ──────────────────────────────────────────────────────────────

-test('YEAR_IMAGES is 8760', () => {
-  assert.strictEqual(YEAR_IMAGES, 8760);
-});
+describe('cycleMonth', () => {
+  it('returns a string', () => {
+    assert.strictEqual(typeof cycleMonth(), 'string');
+  });

-test('MONTH_ANCHOR is 2023-11-13T09:27:00Z', () => {
-  assert.strictEqual(MONTH_ANCHOR.toISOString(), '2023-11-13T09:27:00.000Z');
-});
+  it('result matches /^\\d{3}\\.webp$/', () => {
+    assert.match(cycleMonth(), /^\d{3}\.webp$/);
+  });

-test('YEAR_ANCHOR is 2023-01-01T00:00:00Z', () => {
-  assert.strictEqual(YEAR_ANCHOR.toISOString(), '2023-01-01T00:00:00.000Z');
-});
+  it('result is never 000.webp (images are 1-indexed)', () => {
+    const anchor = MONTH_ANCHOR.getTime();
+    const synodic_ms = SYNODIC_MONTH * 24 * 60 * 60 * 1000;
+    for (let i = 0; i < 100; i++) {
+      const date = new Date(anchor + i * (synodic_ms / 100));
+      assert.notStrictEqual(cycleMonth(date), '000.webp', `Got 000.webp for offset ${i}`);
+    }
+  });

-// ─── cycleMonth: return format ────────────────────────────────────────────────
+  it('at anchor date returns 001.webp (start of synodic cycle)', () => {
+    assert.strictEqual(cycleMonth(MONTH_ANCHOR), '001.webp');
+  });

-test('cycleMonth returns a string', () => {
-  assert.strictEqual(typeof cycleMonth(), 'string');
-});
+  it('one synodic month + 1 min after anchor returns near start of next cycle', () => {
+    const oneMonthPlus = new Date(
+      MONTH_ANCHOR.getTime() + SYNODIC_MONTH * 24 * 60 * 60 * 1000 + 60_000,
+    );
+    const index = parseInt(cycleMonth(oneMonthPlus).replace('.webp', ''), 10);
+    assert(index <= 3, `Expected near start of next cycle (index <= 3), got ${index}`);
+  });

-test('cycleMonth result matches /^\\d{3}\\.webp$/', () => {
-  const result = cycleMonth();
-  assert.match(result, /^\d{3}\.webp$/);
-});
+  it('at halfway through synodic month returns ~354.webp', () => {
+    const half = new Date(MONTH_ANCHOR.getTime() + (SYNODIC_MONTH / 2) * 24 * 60 * 60 * 1000);
+    const index = parseInt(cycleMonth(half).replace('.webp', ''), 10);
+    assert(index >= 353 && index <= 355, `Expected ~354, got ${index}`);
+  });

-test('cycleMonth result is never 000.webp (images are 1-indexed)', () => {
-  // Test many dates across different lunar phases
-  const anchor = MONTH_ANCHOR.getTime();
-  const synodic_ms = SYNODIC_MONTH * 24 * 60 * 60 * 1000;
-  for (let i = 0; i < 100; i++) {
-    const date = new Date(anchor + i * (synodic_ms / 100));
-    const result = cycleMonth(date);
-    assert.notStrictEqual(result, '000.webp', `Got 000.webp for offset ${i}`);
-  }
-});
+  it('result is always in range [001, 708]', () => {
+    const start = new Date('2020-01-01T00:00:00Z');
+    const step = 24 * 60 * 60 * 1000 * 7;
+    for (let i = 0; i < 260; i++) {
+      const date = new Date(start.getTime() + i * step);
+      const index = parseInt(cycleMonth(date).replace('.webp', ''), 10);
+      assert(index >= 1, `Index ${index} below minimum (date: ${date.toISOString()})`);
+      assert(index <= 708, `Index ${index} above maximum (date: ${date.toISOString()})`);
+    }
+  });

-// ─── cycleMonth: anchor date ──────────────────────────────────────────────────
-
-test('cycleMonth at anchor date returns 001.webp (start of synodic cycle)', () => {
-  assert.strictEqual(cycleMonth(MONTH_ANCHOR), '001.webp');
-});
-
-test('cycleMonth one synodic month + 1 min after anchor returns near start of next cycle', () => {
-  // Adding exactly one synodic month in floating-point can land on either side of the
-  // cycle boundary (001 or 708) due to IEEE 754 rounding. Adding 1 minute steps past it.
-  const oneMonthPlus = new Date(
-    MONTH_ANCHOR.getTime() + SYNODIC_MONTH * 24 * 60 * 60 * 1000 + 60_000
-  );
-  const result = cycleMonth(oneMonthPlus);
-  const index = parseInt(result.replace('.webp', ''), 10);
-  assert(index <= 3, `Expected near start of next cycle (index <= 3), got ${index}`);
-});
-
-test('cycleMonth at halfway through synodic month returns ~354.webp', () => {
-  const half = new Date(
-    MONTH_ANCHOR.getTime() + (SYNODIC_MONTH / 2) * 24 * 60 * 60 * 1000
-  );
-  const result = cycleMonth(half);
-  const index = parseInt(result.replace('.webp', ''), 10);
-  // Allow ±1 for rounding
-  assert(index >= 353 && index <= 355, `Expected ~354, got ${index}`);
-});
-
-test('cycleMonth result is always in range [001, 708]', () => {
-  // Test dates spanning 5 years
-  const start = new Date('2020-01-01T00:00:00Z');
-  const step = 24 * 60 * 60 * 1000 * 7; // weekly
-  for (let i = 0; i < 260; i++) {
-    const date = new Date(start.getTime() + i * step);
-    const result = cycleMonth(date);
+  it('handles dates before the anchor (pre-2023)', () => {
+    const past = new Date('2020-06-15T00:00:00Z');
+    const result = cycleMonth(past);
+    assert.match(result, /^\d{3}\.webp$/);
    const index = parseInt(result.replace('.webp', ''), 10);
-    assert(index >= 1, `Index ${index} below minimum (date: ${date.toISOString()})`);
-    assert(index <= 708, `Index ${index} above maximum (date: ${date.toISOString()})`);
-  }
+    assert(index >= 1 && index <= 708);
+  });
+
+  it('with no args returns a valid result', () => {
+    assert.match(cycleMonth(), /^\d{3}\.webp$/);
+  });
+
+  it('throws TypeError for invalid Date', () => {
+    assert.throws(() => cycleMonth(new Date('invalid')), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
+
+  it('throws TypeError for non-Date input', () => {
+    assert.throws(() => cycleMonth('2023-01-01'), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
 });

-// ─── cycleMonth: past dates ───────────────────────────────────────────────────
+// ─── cycleYear ───────────────────────────────────────────────────────────────

-test('cycleMonth handles dates before the anchor (pre-2023)', () => {
-  const past = new Date('2020-06-15T00:00:00Z');
-  const result = cycleMonth(past);
-  assert.match(result, /^\d{3}\.webp$/);
-  const index = parseInt(result.replace('.webp', ''), 10);
-  assert(index >= 1 && index <= 708);
-});
+describe('cycleYear', () => {
+  it('returns a string', () => {
+    assert.strictEqual(typeof cycleYear(), 'string');
+  });

-// ─── cycleYear: return format ─────────────────────────────────────────────────
+  it('result matches /^\\d{4}\\.webp$/', () => {
+    assert.match(cycleYear(), /^\d{4}\.webp$/);
+  });

-test('cycleYear returns a string', () => {
-  assert.strictEqual(typeof cycleYear(), 'string');
-});
+  it('result is never 0000.webp (images are 1-indexed)', () => {
+    const anchor = YEAR_ANCHOR.getTime();
+    const year_ms = YEAR_IMAGES * 60 * 60 * 1000;
+    for (let i = 0; i < 100; i++) {
+      const date = new Date(anchor + i * (year_ms / 100));
+      assert.notStrictEqual(cycleYear(date), '0000.webp', `Got 0000.webp for offset ${i}`);
+    }
+  });

-test('cycleYear result matches /^\\d{4}\\.webp$/', () => {
-  const result = cycleYear();
-  assert.match(result, /^\d{4}\.webp$/);
-});
+  it('at anchor date returns 0001.webp (start of year)', () => {
+    assert.strictEqual(cycleYear(YEAR_ANCHOR), '0001.webp');
+  });

-test('cycleYear result is never 0000.webp (images are 1-indexed)', () => {
-  const anchor = YEAR_ANCHOR.getTime();
-  const year_ms = YEAR_IMAGES * 60 * 60 * 1000;
-  for (let i = 0; i < 100; i++) {
-    const date = new Date(anchor + i * (year_ms / 100));
-    const result = cycleYear(date);
-    assert.notStrictEqual(result, '0000.webp', `Got 0000.webp for offset ${i}`);
-  }
-});
+  it('at exactly one year after anchor returns 0001.webp', () => {
+    const oneYear = new Date(YEAR_ANCHOR.getTime() + YEAR_IMAGES * 60 * 60 * 1000);
+    assert.strictEqual(cycleYear(oneYear), '0001.webp');
+  });

-// ─── cycleYear: anchor date ───────────────────────────────────────────────────
+  it('at halfway through year returns ~4380.webp', () => {
+    const half = new Date(YEAR_ANCHOR.getTime() + (YEAR_IMAGES / 2) * 60 * 60 * 1000);
+    const index = parseInt(cycleYear(half).replace('.webp', ''), 10);
+    assert(index >= 4379 && index <= 4381, `Expected ~4380, got ${index}`);
+  });

-test('cycleYear at anchor date returns 0001.webp (start of year)', () => {
-  assert.strictEqual(cycleYear(YEAR_ANCHOR), '0001.webp');
-});
+  it('result is always in range [0001, 8760]', () => {
+    const start = new Date('2020-01-01T00:00:00Z');
+    const step = 24 * 60 * 60 * 1000 * 7;
+    for (let i = 0; i < 260; i++) {
+      const date = new Date(start.getTime() + i * step);
+      const index = parseInt(cycleYear(date).replace('.webp', ''), 10);
+      assert(index >= 1, `Index ${index} below minimum`);
+      assert(index <= 8760, `Index ${index} above maximum`);
+    }
+  });

-test('cycleYear at exactly one year after anchor returns 0001.webp', () => {
-  const oneYear = new Date(
-    YEAR_ANCHOR.getTime() + YEAR_IMAGES * 60 * 60 * 1000
-  );
-  assert.strictEqual(cycleYear(oneYear), '0001.webp');
-});
-
-test('cycleYear at halfway through year returns ~4380.webp', () => {
-  const half = new Date(
-    YEAR_ANCHOR.getTime() + (YEAR_IMAGES / 2) * 60 * 60 * 1000
-  );
-  const result = cycleYear(half);
-  const index = parseInt(result.replace('.webp', ''), 10);
-  assert(index >= 4379 && index <= 4381, `Expected ~4380, got ${index}`);
-});
-
-test('cycleYear result is always in range [0001, 8760]', () => {
-  const start = new Date('2020-01-01T00:00:00Z');
-  const step = 24 * 60 * 60 * 1000 * 7;
-  for (let i = 0; i < 260; i++) {
-    const date = new Date(start.getTime() + i * step);
-    const result = cycleYear(date);
+  it('handles dates before 2023', () => {
+    const past = new Date('2021-06-15T00:00:00Z');
+    const result = cycleYear(past);
+    assert.match(result, /^\d{4}\.webp$/);
    const index = parseInt(result.replace('.webp', ''), 10);
-    assert(index >= 1, `Index ${index} below minimum`);
-    assert(index <= 8760, `Index ${index} above maximum`);
-  }
+    assert(index >= 1 && index <= 8760);
+  });
+
+  it('with no args returns a valid result', () => {
+    assert.match(cycleYear(), /^\d{4}\.webp$/);
+  });
+
+  it('throws TypeError for invalid Date', () => {
+    assert.throws(() => cycleYear(new Date('invalid')), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
+
+  it('throws TypeError for non-Date input', () => {
+    assert.throws(() => cycleYear('2023-01-01'), {
+      name: 'TypeError',
+      message: 'date must be a valid Date instance',
+    });
+  });
 });

-test('cycleYear handles dates before 2023', () => {
-  const past = new Date('2021-06-15T00:00:00Z');
-  const result = cycleYear(past);
-  assert.match(result, /^\d{4}\.webp$/);
-  const index = parseInt(result.replace('.webp', ''), 10);
-  assert(index >= 1 && index <= 8760);
+// ─── imageFolder ─────────────────────────────────────────────────────────────
+
+describe('imageFolder', () => {
+  it('returns correct folder name', () => {
+    assert.strictEqual(imageFolder('mm', 256, 75), 'mm-256-75');
+    assert.strictEqual(imageFolder('mm', 512, 85), 'mm-512-85');
+    assert.strictEqual(imageFolder('my', 256, 75), 'my-256-75');
+    assert.strictEqual(imageFolder('my', 512, 85), 'my-512-85');
+  });
 });

-// ─── cycleMonth/cycleYear default parameter ───────────────────────────────────
+// ─── cdnUrl ──────────────────────────────────────────────────────────────────

-test('cycleMonth() with no args returns a valid result', () => {
-  const result = cycleMonth();
-  assert.match(result, /^\d{3}\.webp$/);
+describe('cdnUrl', () => {
+  it('returns a valid jsDelivr URL', () => {
+    assert.strictEqual(
+      cdnUrl('354.webp', 'mm', 256, 75),
+      'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/354.webp',
+    );
+  });
+
+  it('respects custom ref parameter', () => {
+    assert.strictEqual(
+      cdnUrl('001.webp', 'my', 512, 85, 'v2.0.0'),
+      'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@v2.0.0/my-512-85/001.webp',
+    );
+  });
+
+  it('integrates with cycleMonth output', () => {
+    const filename = cycleMonth(MONTH_ANCHOR);
+    const url = cdnUrl(filename, 'mm', 256, 75);
+    assert(url.startsWith('https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/'));
+    assert(url.endsWith('.webp'));
+  });
 });
-
-test('cycleYear() with no args returns a valid result', () => {
-  const result = cycleYear();
-  assert.match(result, /^\d{4}\.webp$/);
-});
-
-// ─── imageFolder ──────────────────────────────────────────────────────────────
-
-test('imageFolder returns correct folder name', () => {
-  assert.strictEqual(imageFolder('mm', 256, 75), 'mm-256-75');
-  assert.strictEqual(imageFolder('mm', 512, 85), 'mm-512-85');
-  assert.strictEqual(imageFolder('my', 256, 75), 'my-256-75');
-  assert.strictEqual(imageFolder('my', 512, 85), 'my-512-85');
-});
-
-// ─── cdnUrl ───────────────────────────────────────────────────────────────────
-
-test('cdnUrl returns a valid jsDelivr URL', () => {
-  const url = cdnUrl('354.webp', 'mm', 256, 75);
-  assert.strictEqual(
-    url,
-    'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/354.webp'
-  );
-});
-
-test('cdnUrl respects custom ref parameter', () => {
-  const url = cdnUrl('001.webp', 'my', 512, 85, 'v2.0.0');
-  assert.strictEqual(
-    url,
-    'https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@v2.0.0/my-512-85/001.webp'
-  );
-});
-
-test('cdnUrl integrates with cycleMonth output', () => {
-  const filename = cycleMonth(MONTH_ANCHOR);
-  const url = cdnUrl(filename, 'mm', 256, 75);
-  assert(url.startsWith('https://cdn.jsdelivr.net/gh/acamarata/moon-cycle@main/mm-256-75/'));
-  assert(url.endsWith('.webp'));
-});
-
-// ─── Summary ─────────────────────────────────────────────────────────────────
-
-console.log(`\n${passed}/${total} tests passed`);
-if (passed < total) process.exit(1);
--- a/tsconfig.json
+++ b/tsconfig.json
@ -11,7 +11,10 @@
    "sourceMap": true,
    "outDir": "dist",
    "rootDir": "src",
-    "types": ["node"]
+    "types": ["node"],
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true
  },
  "include": ["src"],
  "exclude": ["node_modules", "dist"]