chore: small tweaks

We don't need to check if fragments are valid in own file.
It's already checked by the rule MD051 of markdownlint (else we have the error duplicated).
Ref: https://github.com/DavidAnson/markdownlint/blob/main/doc/md051.md

.eslintrc.json

@@ -1,7 +1,11 @@
 {
   "extends": ["conventions", "prettier"],
-  "plugins": ["prettier"],
+  "plugins": ["prettier", "import", "unicorn"],
+  "parserOptions": {
+    "project": "./tsconfig.json"
+  },
   "rules": {
-    "prettier/prettier": "error"
+    "prettier/prettier": "error",
+    "import/extensions": ["error", "always"]
   }
 }

.markdownlint-cli2.jsonc

@@ -1,9 +1,9 @@
 {
   "config": {
     "extends": "markdownlint/style/prettier",
-    "relative-links": true,
     "default": true,
-    "MD033": false
+    "relative-links": true,
+    "no-inline-html": false
   },
   "globs": ["**/*.{md,mdx}"],
   "ignores": ["**/node_modules", "**/test/fixtures/**"],

README.md

@@ -10,7 +10,7 @@
   <a href="./CODE_OF_CONDUCT.md"><img src="https://img.shields.io/badge/Contributor%20Covenant-v2.0%20adopted-ff69b4.svg" alt="Contributor Covenant" /></a>
   <br />
   <a href="https://github.com/theoludwig/markdownlint-rule-relative-links/actions/workflows/lint.yml"><img src="https://github.com/theoludwig/markdownlint-rule-relative-links/actions/workflows/lint.yml/badge.svg?branch=develop" alt="Lint" /></a>
-  <a href="https://github.com/theoludwig/markdownlint-rule-relative-linksactions/workflows/test.yml"><img src="https://github.com/theoludwig/markdownlint-rule-relative-links/actions/workflows/test.yml/badge.svg?branch=develop" alt="Test" /></a>
+  <a href="https://github.com/theoludwig/markdownlint-rule-relative-links/actions/workflows/test.yml"><img src="https://github.com/theoludwig/markdownlint-rule-relative-links/actions/workflows/test.yml/badge.svg?branch=develop" alt="Test" /></a>
   <br />
   <a href="https://conventionalcommits.org"><img src="https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg" alt="Conventional Commits" /></a>
   <a href="https://github.com/semantic-release/semantic-release"><img src="https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg" alt="semantic-release" /></a>
@@ -49,13 +49,12 @@ awesome.md:3 relative-links Relative links should be valid ["./invalid.txt" shou
 ### Additional features
 
 - Support images (e.g: `![Image](./image.png)`).
-- Support anchors (heading fragment links) (e.g: `[Link](./awesome.md#existing-heading)`).
+- Support links fragments similar to the [built-in `markdownlint` rule - MD051](https://github.com/DavidAnson/markdownlint/blob/main/doc/md051.md) (e.g: `[Link](./awesome.md#heading)`).
 - Ignore external links and absolute paths as it only checks relative links (e.g: `https://example.com/` or `/absolute/path.png`).
 
 ### Limitations
 
-- Only images and links defined using markdown syntax are supported, html syntax is not supported (e.g: `<a href="./link.txt" />` or `<img src="./image.png" />`).
+- Only images and links defined using markdown syntax are validated, html syntax is ignored (e.g: `<a href="./link.txt" />` or `<img src="./image.png" />`).
-- Anchors checking is limited to headings, other elements are not supported (e.g: with a "id", `<div id="anchor" />`).
 
 Contributions are welcome to improve the rule, and to alleviate these limitations. See [CONTRIBUTING.md](./CONTRIBUTING.md) for more information.
 

jsconfig.json

@@ -9,6 +9,7 @@
     "noEmit": true,
     "rootDir": ".",
     "baseUrl": ".",
+    "skipLibCheck": true,
     "strict": true,
     "allowUnusedLabels": false,
     "allowUnreachableCode": false,

package-lock.json

@@ -16,13 +16,13 @@
         "@commitlint/cli": "18.4.4",
         "@commitlint/config-conventional": "18.4.4",
         "@types/markdown-it": "13.0.7",
-        "@types/node": "20.10.8",
+        "@types/node": "20.11.0",
         "editorconfig-checker": "5.1.2",
         "eslint": "8.56.0",
         "eslint-config-conventions": "13.1.0",
         "eslint-config-prettier": "9.1.0",
         "eslint-plugin-import": "2.29.1",
-        "eslint-plugin-prettier": "5.1.2",
+        "eslint-plugin-prettier": "5.1.3",
         "eslint-plugin-promise": "6.1.1",
         "eslint-plugin-unicorn": "50.0.1",
         "husky": "8.0.3",
@@ -557,13 +557,13 @@
       }
     },
     "node_modules/@humanwhocodes/config-array": {
-      "version": "0.11.13",
+      "version": "0.11.14",
-      "resolved": "https://registry.npmjs.org/@humanwhocodes/config-array/-/config-array-0.11.13.tgz",
+      "resolved": "https://registry.npmjs.org/@humanwhocodes/config-array/-/config-array-0.11.14.tgz",
-      "integrity": "sha512-JSBDMiDKSzQVngfRjOdFXgFfklaXI4K9nLF49Auh21lmBWRLIK3+xTErTWD4KU54pb6coM6ESE7Awz/FNU3zgQ==",
+      "integrity": "sha512-3T8LkOmg45BV5FICb15QQMsyUSWrQ8AygVfC7ZG32zOalnqrilm018ZVCw0eapXux8FtA33q8PSRSstjee3jSg==",
       "dev": true,
       "dependencies": {
-        "@humanwhocodes/object-schema": "^2.0.1",
+        "@humanwhocodes/object-schema": "^2.0.2",
-        "debug": "^4.1.1",
+        "debug": "^4.3.1",
         "minimatch": "^3.0.5"
       },
       "engines": {
@@ -584,9 +584,9 @@
       }
     },
     "node_modules/@humanwhocodes/object-schema": {
-      "version": "2.0.1",
+      "version": "2.0.2",
-      "resolved": "https://registry.npmjs.org/@humanwhocodes/object-schema/-/object-schema-2.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/@humanwhocodes/object-schema/-/object-schema-2.0.2.tgz",
-      "integrity": "sha512-dvuCeX5fC9dXgJn9t+X5atfmgQAzUOWqS1254Gh0m6i8wKd10ebXkfNKiRK+1GWi/yTvvLDHpoxLr0xxxeslWw==",
+      "integrity": "sha512-6EwiSjwWYP7pTckG6I5eyFANjPhmPjUX9JRLUSfNPC7FX7zK9gyZAfUEaECL6ALTpGX5AjnBq3C9XmVWPitNpw==",
       "dev": true
     },
     "node_modules/@nodelib/fs.scandir": {
@@ -1325,9 +1325,9 @@
       "dev": true
     },
     "node_modules/@types/node": {
-      "version": "20.10.8",
+      "version": "20.11.0",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-20.10.8.tgz",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-20.11.0.tgz",
-      "integrity": "sha512-f8nQs3cLxbAFc00vEU59yf9UyGUftkPaLGfvbVOIDdx2i1b8epBqj2aNGyP19fiyXWvlmZ7qC1XLjAzw/OKIeA==",
+      "integrity": "sha512-o9bjXmDNcF7GbM4CNQpmi+TutCgap/K3w1JyKgxAjqx41zp9qlIAVFi0IhCNsJcXolEqLWhbFbEeL0PvYm4pcQ==",
       "dev": true,
       "dependencies": {
         "undici-types": "~5.26.4"
@@ -2422,9 +2422,9 @@
       }
     },
     "node_modules/electron-to-chromium": {
-      "version": "1.4.625",
+      "version": "1.4.628",
-      "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.4.625.tgz",
+      "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.4.628.tgz",
-      "integrity": "sha512-DENMhh3MFgaPDoXWrVIqSPInQoLImywfCwrSmVl3cf9QHzoZSiutHwGaB/Ql3VkqcQV30rzgdM+BjKqBAJxo5Q==",
+      "integrity": "sha512-2k7t5PHvLsufpP6Zwk0nof62yLOsCf032wZx7/q0mv8gwlXjhcxI3lz6f0jBr0GrnWKcm3burXzI3t5IrcdUxw==",
       "dev": true
     },
     "node_modules/emoji-regex": {
@@ -2911,9 +2911,9 @@
       }
     },
     "node_modules/eslint-plugin-prettier": {
-      "version": "5.1.2",
+      "version": "5.1.3",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-prettier/-/eslint-plugin-prettier-5.1.2.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-prettier/-/eslint-plugin-prettier-5.1.3.tgz",
-      "integrity": "sha512-dhlpWc9vOwohcWmClFcA+HjlvUpuyynYs0Rf+L/P6/0iQE6vlHW9l5bkfzN62/Stm9fbq8ku46qzde76T1xlSg==",
+      "integrity": "sha512-C9GCVAs4Eq7ZC/XFQHITLiHJxQngdtraXaM+LoUFoFp/lHNl2Zn8f3WQbe9HvTBBQ9YnKFB0/2Ajdqwo5D1EAw==",
       "dev": true,
       "dependencies": {
         "prettier-linter-helpers": "^1.0.0",
@@ -5410,9 +5410,9 @@
       }
     },
     "node_modules/npm": {
-      "version": "10.2.5",
+      "version": "10.3.0",
-      "resolved": "https://registry.npmjs.org/npm/-/npm-10.2.5.tgz",
+      "resolved": "https://registry.npmjs.org/npm/-/npm-10.3.0.tgz",
-      "integrity": "sha512-lXdZ7titEN8CH5YJk9C/aYRU9JeDxQ4d8rwIIDsvH3SMjLjHTukB2CFstMiB30zXs4vCrPN2WH6cDq1yHBeJAw==",
+      "integrity": "sha512-9u5GFc1UqI2DLlGI7QdjkpIaBs3UhTtY8KoCqYJK24gV/j/tByaI4BA4R7RkOc+ASqZMzFPKt4Pj2Z8JcGo//A==",
       "bundleDependencies": [
         "@isaacs/string-locale-compare",
         "@npmcli/arborist",
@@ -5494,12 +5494,12 @@
         "@npmcli/fs": "^3.1.0",
         "@npmcli/map-workspaces": "^3.0.4",
         "@npmcli/package-json": "^5.0.0",
-        "@npmcli/promise-spawn": "^7.0.0",
+        "@npmcli/promise-spawn": "^7.0.1",
-        "@npmcli/run-script": "^7.0.2",
+        "@npmcli/run-script": "^7.0.3",
         "@sigstore/tuf": "^2.2.0",
         "abbrev": "^2.0.0",
         "archy": "~1.0.0",
-        "cacache": "^18.0.1",
+        "cacache": "^18.0.2",
         "chalk": "^5.3.0",
         "ci-info": "^4.0.0",
         "cli-columns": "^4.0.0",
@@ -5653,7 +5653,7 @@
       }
     },
     "node_modules/npm/node_modules/@npmcli/arborist": {
-      "version": "7.2.2",
+      "version": "7.3.0",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -5700,7 +5700,7 @@
       }
     },
     "node_modules/npm/node_modules/@npmcli/config": {
-      "version": "8.0.3",
+      "version": "8.1.0",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -5758,7 +5758,7 @@
       }
     },
     "node_modules/npm/node_modules/@npmcli/git": {
-      "version": "5.0.3",
+      "version": "5.0.4",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -5859,7 +5859,7 @@
       }
     },
     "node_modules/npm/node_modules/@npmcli/promise-spawn": {
-      "version": "7.0.0",
+      "version": "7.0.1",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -5883,7 +5883,7 @@
       }
     },
     "node_modules/npm/node_modules/@npmcli/run-script": {
-      "version": "7.0.2",
+      "version": "7.0.3",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -5987,18 +5987,6 @@
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
     },
-    "node_modules/npm/node_modules/abort-controller": {
-      "version": "3.0.0",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "dependencies": {
-        "event-target-shim": "^5.0.0"
-      },
-      "engines": {
-        "node": ">=6.5"
-      }
-    },
     "node_modules/npm/node_modules/agent-base": {
       "version": "7.1.0",
       "dev": true,
@@ -6061,14 +6049,10 @@
       "license": "MIT"
     },
     "node_modules/npm/node_modules/are-we-there-yet": {
-      "version": "4.0.1",
+      "version": "4.0.2",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
-      "dependencies": {
-        "delegates": "^1.0.0",
-        "readable-stream": "^4.1.0"
-      },
       "engines": {
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
@@ -6079,26 +6063,6 @@
       "inBundle": true,
       "license": "MIT"
     },
-    "node_modules/npm/node_modules/base64-js": {
-      "version": "1.5.1",
-      "dev": true,
-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "inBundle": true,
-      "license": "MIT"
-    },
     "node_modules/npm/node_modules/bin-links": {
       "version": "4.0.3",
       "dev": true,
@@ -6132,30 +6096,6 @@
         "balanced-match": "^1.0.0"
       }
     },
-    "node_modules/npm/node_modules/buffer": {
-      "version": "6.0.3",
-      "dev": true,
-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "inBundle": true,
-      "license": "MIT",
-      "dependencies": {
-        "base64-js": "^1.3.1",
-        "ieee754": "^1.2.1"
-      }
-    },
     "node_modules/npm/node_modules/builtins": {
       "version": "5.0.1",
       "dev": true,
@@ -6166,7 +6106,7 @@
       }
     },
     "node_modules/npm/node_modules/cacache": {
-      "version": "18.0.1",
+      "version": "18.0.2",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -6461,12 +6401,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/npm/node_modules/delegates": {
-      "version": "1.0.0",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT"
-    },
     "node_modules/npm/node_modules/diff": {
       "version": "5.1.0",
       "dev": true,
@@ -6513,24 +6447,6 @@
       "inBundle": true,
       "license": "MIT"
     },
-    "node_modules/npm/node_modules/event-target-shim": {
-      "version": "5.0.1",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=6"
-      }
-    },
-    "node_modules/npm/node_modules/events": {
-      "version": "3.3.0",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=0.8.x"
-      }
-    },
     "node_modules/npm/node_modules/exponential-backoff": {
       "version": "3.1.1",
       "dev": true,
@@ -6726,26 +6642,6 @@
         "node": ">=0.10.0"
       }
     },
-    "node_modules/npm/node_modules/ieee754": {
-      "version": "1.2.1",
-      "dev": true,
-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "inBundle": true,
-      "license": "BSD-3-Clause"
-    },
     "node_modules/npm/node_modules/ignore-walk": {
       "version": "6.0.4",
       "dev": true,
@@ -6937,7 +6833,7 @@
       }
     },
     "node_modules/npm/node_modules/libnpmdiff": {
-      "version": "6.0.4",
+      "version": "6.0.5",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -6957,7 +6853,7 @@
       }
     },
     "node_modules/npm/node_modules/libnpmexec": {
-      "version": "7.0.5",
+      "version": "7.0.6",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -6979,7 +6875,7 @@
       }
     },
     "node_modules/npm/node_modules/libnpmfund": {
-      "version": "5.0.2",
+      "version": "5.0.3",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -7017,7 +6913,7 @@
       }
     },
     "node_modules/npm/node_modules/libnpmpack": {
-      "version": "6.0.4",
+      "version": "6.0.5",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -7442,7 +7338,7 @@
       }
     },
     "node_modules/npm/node_modules/npm-packlist": {
-      "version": "8.0.1",
+      "version": "8.0.2",
       "dev": true,
       "inBundle": true,
       "license": "ISC",
@@ -7610,7 +7506,7 @@
       }
     },
     "node_modules/npm/node_modules/postcss-selector-parser": {
-      "version": "6.0.13",
+      "version": "6.0.15",
       "dev": true,
       "inBundle": true,
       "license": "MIT",
@@ -7631,15 +7527,6 @@
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
     },
-    "node_modules/npm/node_modules/process": {
-      "version": "0.11.10",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">= 0.6.0"
-      }
-    },
     "node_modules/npm/node_modules/promise-all-reject-late": {
       "version": "1.0.1",
       "dev": true,
@@ -7746,22 +7633,6 @@
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
     },
-    "node_modules/npm/node_modules/readable-stream": {
-      "version": "4.4.2",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "dependencies": {
-        "abort-controller": "^3.0.0",
-        "buffer": "^6.0.3",
-        "events": "^3.3.0",
-        "process": "^0.11.10",
-        "string_decoder": "^1.3.0"
-      },
-      "engines": {
-        "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
-      }
-    },
     "node_modules/npm/node_modules/retry": {
       "version": "0.12.0",
       "dev": true,
@@ -7771,26 +7642,6 @@
         "node": ">= 4"
       }
     },
-    "node_modules/npm/node_modules/safe-buffer": {
-      "version": "5.2.1",
-      "dev": true,
-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "inBundle": true,
-      "license": "MIT"
-    },
     "node_modules/npm/node_modules/safer-buffer": {
       "version": "2.1.2",
       "dev": true,
@@ -7961,15 +7812,6 @@
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
     },
-    "node_modules/npm/node_modules/string_decoder": {
-      "version": "1.3.0",
-      "dev": true,
-      "inBundle": true,
-      "license": "MIT",
-      "dependencies": {
-        "safe-buffer": "~5.2.0"
-      }
-    },
     "node_modules/npm/node_modules/string-width": {
       "version": "4.2.3",
       "dev": true,
@@ -9296,9 +9138,9 @@
       "dev": true
     },
     "node_modules/safe-regex-test": {
-      "version": "1.0.1",
+      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/safe-regex-test/-/safe-regex-test-1.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/safe-regex-test/-/safe-regex-test-1.0.2.tgz",
-      "integrity": "sha512-Y5NejJTTliTyY4H7sipGqY+RX5P87i3F7c4Rcepy72nq+mNLhIsD0W4c7kEmduMDQCSqtPsXPlSTsFhh2LQv+g==",
+      "integrity": "sha512-83S9w6eFq12BBIJYvjMux6/dkirb8+4zJRA9cxNBVb7Wq5fJBW+Xze48WqR8pxua7bDuAaaAxtVVd4Idjp1dBQ==",
       "dev": true,
       "dependencies": {
         "call-bind": "^1.0.5",

package.json

@@ -37,7 +37,7 @@
     "lint:prettier": "prettier . --check --ignore-path .gitignore",
     "lint:javascript": "tsc --project jsconfig.json --noEmit",
     "lint:staged": "lint-staged",
-    "test": "node --test --experimental-test-coverage ./test",
+    "test": "node --test --experimental-test-coverage",
     "release": "semantic-release",
     "postinstall": "husky install",
     "prepublishOnly": "pinst --disable",
@@ -50,13 +50,13 @@
     "@commitlint/cli": "18.4.4",
     "@commitlint/config-conventional": "18.4.4",
     "@types/markdown-it": "13.0.7",
-    "@types/node": "20.10.8",
+    "@types/node": "20.11.0",
     "editorconfig-checker": "5.1.2",
     "eslint": "8.56.0",
     "eslint-config-conventions": "13.1.0",
     "eslint-config-prettier": "9.1.0",
     "eslint-plugin-import": "2.29.1",
-    "eslint-plugin-prettier": "5.1.2",
+    "eslint-plugin-prettier": "5.1.3",
     "eslint-plugin-promise": "6.1.1",
     "eslint-plugin-unicorn": "50.0.1",
     "husky": "8.0.3",

src/index.js

@@ -3,10 +3,11 @@
 const { pathToFileURL } = require("node:url")
 const fs = require("node:fs")
 
+const { filterTokens } = require("./markdownlint-rule-helpers/helpers.js")
 const {
-  filterTokens,
   convertHeadingToHTMLFragment,
   getMarkdownHeadings,
+  getMarkdownIdOrAnchorNameFragments,
 } = require("./utils.js")
 
 /** @typedef {import('markdownlint').Rule} MarkdownLintRule */
@@ -45,46 +46,83 @@ const customRule = {
           }
         }
 
-        if (hrefSrc != null) {
+        if (hrefSrc == null) {
-          const url = new URL(hrefSrc, pathToFileURL(params.name))
+          continue
-          const isRelative =
+        }
-            url.protocol === "file:" && !hrefSrc.startsWith("/")
-          if (isRelative) {
-            const detail = `"${hrefSrc}"`
 
-            if (!fs.existsSync(url)) {
+        const url = new URL(hrefSrc, pathToFileURL(params.name))
+        const isRelative =
+          url.protocol === "file:" &&
+          !hrefSrc.startsWith("/") &&
+          !hrefSrc.startsWith("#")
+
+        if (!isRelative) {
+          continue
+        }
+
+        const detail = `"${hrefSrc}"`
+
+        if (!fs.existsSync(url)) {
+          onError({
+            lineNumber,
+            detail: `${detail} should exist in the file system`,
+          })
+          continue
+        }
+
+        if (url.hash.length <= 0) {
+          if (hrefSrc.includes("#")) {
+            if (type !== "link_open") {
               onError({
                 lineNumber,
-                detail: `${detail} should exist in the file system`,
+                detail: `${detail} should not have a fragment identifier as it is an image`,
               })
               continue
             }
 
-            if (type === "link_open" && url.hash !== "") {
+            onError({
-              const fileContent = fs.readFileSync(url, { encoding: "utf8" })
+              lineNumber,
-              const headings = getMarkdownHeadings(fileContent)
+              detail: `${detail} should have a valid fragment identifier`,
-
+            })
-              /** @type {Map<string, number>} */
+            continue
-              const fragments = new Map()
-
-              const headingsHTMLFragments = headings.map((heading) => {
-                const fragment = convertHeadingToHTMLFragment(heading)
-                const count = fragments.get(fragment) ?? 0
-                fragments.set(fragment, count + 1)
-                if (count !== 0) {
-                  return `${fragment}-${count}`
-                }
-                return fragment
-              })
-
-              if (!headingsHTMLFragments.includes(url.hash)) {
-                onError({
-                  lineNumber,
-                  detail: `${detail} should have a valid fragment identifier`,
-                })
-              }
-            }
           }
+          continue
+        }
+
+        if (type !== "link_open") {
+          onError({
+            lineNumber,
+            detail: `${detail} should not have a fragment identifier as it is an image`,
+          })
+          continue
+        }
+
+        const fileContent = fs.readFileSync(url, { encoding: "utf8" })
+        const headings = getMarkdownHeadings(fileContent)
+        const idOrAnchorNameHTMLFragments =
+          getMarkdownIdOrAnchorNameFragments(fileContent)
+
+        /** @type {Map<string, number>} */
+        const fragments = new Map()
+
+        const fragmentsHTML = headings.map((heading) => {
+          const fragment = convertHeadingToHTMLFragment(heading)
+          const count = fragments.get(fragment) ?? 0
+          fragments.set(fragment, count + 1)
+          if (count !== 0) {
+            return `${fragment}-${count}`
+          }
+          return fragment
+        })
+
+        fragmentsHTML.push(...idOrAnchorNameHTMLFragments)
+
+        if (!fragmentsHTML.includes(url.hash)) {
+          onError({
+            lineNumber,
+            detail: `${detail} should have a valid fragment identifier`,
+          })
+          continue
         }
       }
     })

src/markdownlint-rule-helpers/helpers.js

@@ -0,0 +1,38 @@
+/**
+ * Dependency Vendoring of `markdownlint-rule-helpers`
+ * @see https://www.npmjs.com/package/markdownlint-rule-helpers
+ */
+
+/** @typedef {import('markdownlint').RuleParams} MarkdownLintRuleParams */
+/** @typedef {import('markdownlint').MarkdownItToken} MarkdownItToken */
+
+/**
+ * Calls the provided function for each matching token.
+ *
+ * @param {MarkdownLintRuleParams} params RuleParams instance.
+ * @param {string} type Token type identifier.
+ * @param {(token: MarkdownItToken) => void} handler Callback function.
+ * @returns {void}
+ */
+const filterTokens = (params, type, handler) => {
+  for (const token of params.tokens) {
+    if (token.type === type) {
+      handler(token)
+    }
+  }
+}
+
+/**
+ * Gets a Regular Expression for matching the specified HTML attribute.
+ *
+ * @param {string} name HTML attribute name.
+ * @returns {RegExp} Regular Expression for matching.
+ */
+const getHtmlAttributeRe = (name) => {
+  return new RegExp(`\\s${name}\\s*=\\s*['"]?([^'"\\s>]*)`, "iu")
+}
+
+module.exports = {
+  filterTokens,
+  getHtmlAttributeRe,
+}

src/utils.js

@@ -1,23 +1,6 @@
 const MarkdownIt = require("markdown-it")
 
-/** @typedef {import('markdownlint').RuleParams} MarkdownLintRuleParams */
+const { getHtmlAttributeRe } = require("./markdownlint-rule-helpers/helpers.js")
-/** @typedef {import('markdownlint').MarkdownItToken} MarkdownItToken */
-
-/**
- * Calls the provided function for each matching token.
- *
- * @param {MarkdownLintRuleParams} params RuleParams instance.
- * @param {string} type Token type identifier.
- * @param {(token: MarkdownItToken) => void} handler Callback function.
- * @returns {void}
- */
-const filterTokens = (params, type, handler) => {
-  for (const token of params.tokens) {
-    if (token.type === type) {
-      handler(token)
-    }
-  }
-}
 
 /**
  * Converts a Markdown heading into an HTML fragment according to the rules
@@ -94,8 +77,45 @@ const getMarkdownHeadings = (content) => {
   return headings
 }
 
+const nameHTMLAttributeRegex = getHtmlAttributeRe("name")
+const idHTMLAttributeRegex = getHtmlAttributeRe("id")
+
+/**
+ * Gets the id or anchor name fragments from a Markdown string.
+ * @param {string} content
+ * @returns {string[]}
+ */
+const getMarkdownIdOrAnchorNameFragments = (content) => {
+  const markdownIt = new MarkdownIt({ html: true })
+  const tokens = markdownIt.parse(content, {})
+
+  /** @type {string[]} */
+  const result = []
+
+  for (const token of tokens) {
+    const regexMatch =
+      idHTMLAttributeRegex.exec(token.content) ||
+      nameHTMLAttributeRegex.exec(token.content)
+    if (regexMatch == null) {
+      continue
+    }
+
+    const idOrName = regexMatch[1]
+    if (idOrName == null || idOrName.length <= 0) {
+      continue
+    }
+
+    const htmlFragment = "#" + idOrName
+    if (!result.includes(htmlFragment)) {
+      result.push(htmlFragment)
+    }
+  }
+
+  return result
+}
+
 module.exports = {
-  filterTokens,
   convertHeadingToHTMLFragment,
   getMarkdownHeadings,
+  getMarkdownIdOrAnchorNameFragments,
 }

test/fixtures/invalid/empty-id-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<div id>Content</div>

test/fixtures/invalid/empty-id-fragment/empty-id-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Link fragment](./awesome.md#)

test/fixtures/invalid/ignore-empty-fragment-checking-for-image.md

@@ -0,0 +1,3 @@
+# Invalid
+
+![Image](../image.png#)

test/fixtures/invalid/ignore-fragment-checking-for-image.md

@@ -0,0 +1,3 @@
+# Invalid
+
+![Image](../image.png#non-existing-fragment)

test/fixtures/invalid/ignore-name-fragment-if-not-an-anchor/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<input name="name-should-be-ignored" id="id-after-name" />

test/fixtures/invalid/ignore-name-fragment-if-not-an-anchor/ignore-name-fragment-if-not-an-anchor.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Invalid](./awesome.md#name-should-be-ignored)

test/fixtures/invalid/ignore-not-an-id-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<div data-id="not-an-id-should-be-ignored">Content</div>

test/fixtures/invalid/ignore-not-an-id-fragment/ignore-not-an-id-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Invalid](./awesome.md#not-an-id-should-be-ignored)

test/fixtures/invalid/non-existing-anchor-name-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<a name="existing-heading-anchor">Link</a>

test/fixtures/invalid/non-existing-anchor-name-fragment/non-existing-anchor-name-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Link fragment](./awesome.md#non-existing-anchor-name-fragment)

test/fixtures/invalid/non-existing-element-id-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<div id="existing-element-id-fragment">Content</div>

test/fixtures/invalid/non-existing-element-id-fragment/non-existing-element-id-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Link fragment](./awesome.md#non-existing-element-id-fragment)

test/fixtures/invalid/non-existing-heading-fragment/awesome.md

@@ -1,3 +1,3 @@
-# Valid
+# Awesome
 
 ## Existing Heading

test/fixtures/valid/existing-anchor-name-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<a name="existing-heading-anchor">Link</a>

test/fixtures/valid/existing-anchor-name-fragment/existing-anchor-name-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Link fragment](./awesome.md#existing-heading-anchor)

test/fixtures/valid/existing-element-id-fragment/awesome.md

@@ -0,0 +1,3 @@
+# Awesome
+
+<div id="existing-element-id-fragment">Content</div>

test/fixtures/valid/existing-element-id-fragment/existing-element-id-fragment.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[Link fragment](./awesome.md#existing-element-id-fragment)

test/fixtures/valid/existing-image.md

@@ -1,3 +1,3 @@
 # Valid
 
-![Image](./image.png)
+![Image](../image.png)

test/fixtures/valid/ignore-fragment-checking-in-own-file.md

@@ -0,0 +1,5 @@
+# Valid
+
+<div id="existing-element-id-fragment">Content</div>
+
+[Link fragment](#non-existing-element-id-fragment)

test/index.test.js

@@ -23,90 +23,134 @@ const validateMarkdownLint = async (fixtureFile) => {
 }
 
 test("ensure the rule validates correctly", async (t) => {
-  await t.test("should be valid", async (t) => {
+  await t.test("should be invalid", async (t) => {
-    await t.test("with an existing heading fragment", async () => {
+    const testCases = [
-      const lintResults = await validateMarkdownLint(
+      {
-        "test/fixtures/valid/existing-heading-fragment/existing-heading-fragment.md",
+        name: "with an empty id fragment",
-      )
+        fixturePath:
-      assert.equal(lintResults?.length, 0)
+          "test/fixtures/invalid/empty-id-fragment/empty-id-fragment.md",
-    })
+        error: '"./awesome.md#" should have a valid fragment identifier',
+      },
+      {
+        name: "with a name fragment other than for an anchor",
+        fixturePath:
+          "test/fixtures/invalid/ignore-name-fragment-if-not-an-anchor/ignore-name-fragment-if-not-an-anchor.md",
+        error:
+          '"./awesome.md#name-should-be-ignored" should have a valid fragment identifier',
+      },
+      {
+        name: "with a non-existing id fragment (data-id !== id)",
+        fixturePath:
+          "test/fixtures/invalid/ignore-not-an-id-fragment/ignore-not-an-id-fragment.md",
+        error:
+          '"./awesome.md#not-an-id-should-be-ignored" should have a valid fragment identifier',
+      },
+      {
+        name: "with a non-existing anchor name fragment",
+        fixturePath:
+          "test/fixtures/invalid/non-existing-anchor-name-fragment/non-existing-anchor-name-fragment.md",
+        error:
+          '"./awesome.md#non-existing-anchor-name-fragment" should have a valid fragment identifier',
+      },
+      {
+        name: "with a non-existing element id fragment",
+        fixturePath:
+          "test/fixtures/invalid/non-existing-element-id-fragment/non-existing-element-id-fragment.md",
+        error:
+          '"./awesome.md#non-existing-element-id-fragment" should have a valid fragment identifier',
+      },
+      {
+        name: "with a non-existing heading fragment",
+        fixturePath:
+          "test/fixtures/invalid/non-existing-heading-fragment/non-existing-heading-fragment.md",
+        error:
+          '"./awesome.md#non-existing-heading" should have a valid fragment identifier',
+      },
+      {
+        name: "with a link to an image with a empty fragment",
+        fixturePath:
+          "test/fixtures/invalid/ignore-empty-fragment-checking-for-image.md",
+        error:
+          '"../image.png#" should not have a fragment identifier as it is an image',
+      },
+      {
+        name: "with a link to an image with a fragment",
+        fixturePath:
+          "test/fixtures/invalid/ignore-fragment-checking-for-image.md",
+        error:
+          '"../image.png#non-existing-fragment" should not have a fragment identifier as it is an image',
+      },
+      {
+        name: "with a non-existing file",
+        fixturePath: "test/fixtures/invalid/non-existing-file.md",
+        error: '"./index.test.js" should exist in the file system',
+      },
+      {
+        name: "with a non-existing image",
+        fixturePath: "test/fixtures/invalid/non-existing-image.md",
+        error: '"./image.png" should exist in the file system',
+      },
+    ]
 
-    await t.test("with an existing file", async () => {
+    for (const { name, fixturePath, error } of testCases) {
-      const lintResults = await validateMarkdownLint(
+      await t.test(name, async () => {
-        "test/fixtures/valid/existing-file.md",
+        const lintResults = await validateMarkdownLint(fixturePath)
-      )
+        assert.equal(lintResults?.length, 1)
-      assert.equal(lintResults?.length, 0)
+        assert.deepEqual(lintResults?.[0]?.ruleNames, relativeLinksRule.names)
-    })
+        assert.equal(
-
+          lintResults?.[0]?.ruleDescription,
-    await t.test("with an existing image", async () => {
+          relativeLinksRule.description,
-      const lintResults = await validateMarkdownLint(
+        )
-        "test/fixtures/valid/existing-image.md",
+        assert.equal(lintResults?.[0]?.errorDetail, error)
-      )
+      })
-      assert.equal(lintResults?.length, 0)
+    }
-    })
-
-    await t.test("should ignore absolute paths", async () => {
-      const lintResults = await validateMarkdownLint(
-        "test/fixtures/valid/ignore-absolute-paths.md",
-      )
-      assert.equal(lintResults?.length, 0)
-    })
-
-    await t.test("should ignore external links", async () => {
-      const lintResults = await validateMarkdownLint(
-        "test/fixtures/valid/ignore-external-links.md",
-      )
-      assert.equal(lintResults?.length, 0)
-    })
   })
 
-  await t.test("should be invalid", async (t) => {
+  await t.test("should be valid", async (t) => {
-    await t.test("with a non-existing heading fragment", async () => {
+    const testCases = [
-      const lintResults = await validateMarkdownLint(
+      {
-        "test/fixtures/invalid/non-existing-heading-fragment/non-existing-heading-fragment.md",
+        name: "with an existing anchor name fragment",
-      )
+        fixturePath:
-      assert.equal(lintResults?.length, 1)
+          "test/fixtures/valid/existing-anchor-name-fragment/existing-anchor-name-fragment.md",
-      assert.deepEqual(lintResults?.[0]?.ruleNames, relativeLinksRule.names)
+      },
-      assert.equal(
+      {
-        lintResults?.[0]?.ruleDescription,
+        name: "with an existing element id fragment",
-        relativeLinksRule.description,
+        fixturePath:
-      )
+          "test/fixtures/valid/existing-element-id-fragment/existing-element-id-fragment.md",
-      assert.equal(
+      },
-        lintResults?.[0]?.errorDetail,
+      {
-        '"./awesome.md#non-existing-heading" should have a valid fragment identifier',
+        name: "with an existing heading fragment",
-      )
+        fixturePath:
-    })
+          "test/fixtures/valid/existing-heading-fragment/existing-heading-fragment.md",
+      },
+      {
+        name: "with an existing file",
+        fixturePath: "test/fixtures/valid/existing-file.md",
+      },
+      {
+        name: "with an existing image",
+        fixturePath: "test/fixtures/valid/existing-image.md",
+      },
+      {
+        name: "should ignore absolute paths",
+        fixturePath: "test/fixtures/valid/ignore-absolute-paths.md",
+      },
+      {
+        name: "should ignore external links",
+        fixturePath: "test/fixtures/valid/ignore-external-links.md",
+      },
+      {
+        name: "should ignore checking fragment in own file",
+        fixturePath:
+          "test/fixtures/valid/ignore-fragment-checking-in-own-file.md",
+      },
+    ]
 
-    await t.test("with a non-existing file", async () => {
+    for (const { name, fixturePath } of testCases) {
-      const lintResults = await validateMarkdownLint(
+      await t.test(name, async () => {
-        "test/fixtures/invalid/non-existing-file.md",
+        const lintResults = await validateMarkdownLint(fixturePath)
-      )
+        assert.equal(lintResults?.length, 0)
-      assert.equal(lintResults?.length, 1)
+      })
-      assert.deepEqual(lintResults?.[0]?.ruleNames, relativeLinksRule.names)
+    }
-      assert.equal(
-        lintResults?.[0]?.ruleDescription,
-        relativeLinksRule.description,
-      )
-      assert.equal(
-        lintResults?.[0]?.errorDetail,
-        '"./index.test.js" should exist in the file system',
-      )
-    })
-
-    await t.test("with a non-existing image", async () => {
-      const lintResults = await validateMarkdownLint(
-        "test/fixtures/invalid/non-existing-image.md",
-      )
-      assert.equal(lintResults?.length, 1)
-      assert.deepEqual(lintResults?.[0]?.ruleNames, relativeLinksRule.names)
-      assert.equal(
-        lintResults?.[0]?.ruleDescription,
-        relativeLinksRule.description,
-      )
-      assert.equal(
-        lintResults?.[0]?.errorDetail,
-        '"./image.png" should exist in the file system',
-      )
-    })
   })
 })

test/utils.test.js

@@ -4,6 +4,7 @@ const assert = require("node:assert/strict")
 const {
   convertHeadingToHTMLFragment,
   getMarkdownHeadings,
+  getMarkdownIdOrAnchorNameFragments,
 } = require("../src/utils.js")
 
 test("utils", async (t) => {
@@ -34,4 +35,23 @@ test("utils", async (t) => {
       ["Hello", "World", "Hello, world!"],
     )
   })
+
+  await t.test("getMarkdownIdOrAnchorNameFragments", async () => {
+    assert.deepStrictEqual(
+      getMarkdownIdOrAnchorNameFragments(
+        '<a name="anchorName" id="anchorId">Link</a>',
+      ),
+      ["#anchorId"],
+    )
+    assert.deepStrictEqual(
+      getMarkdownIdOrAnchorNameFragments('<a name="anchorName">Link</a>'),
+      ["#anchorName"],
+    )
+    assert.deepStrictEqual(
+      getMarkdownIdOrAnchorNameFragments("<a>Link</a>"),
+      [],
+    )
+    assert.deepStrictEqual(getMarkdownIdOrAnchorNameFragments("<a>"), [])
+    assert.deepStrictEqual(getMarkdownIdOrAnchorNameFragments("<a id=>"), [])
+  })
 })