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"]
   }
 }

.github/ISSUE_TEMPLATE/BUG.md

@@ -1,8 +1,8 @@
 ---
-name: '🐛 Bug Report'
+name: "🐛 Bug Report"
-about: 'Report an unexpected problem or unintended behavior.'
+about: "Report an unexpected problem or unintended behavior."
-title: '[Bug]'
+title: "[Bug]"
-labels: 'bug'
+labels: "bug"
 ---
 
 <!--

.github/ISSUE_TEMPLATE/DOCUMENTATION.md

@@ -1,8 +1,8 @@
 ---
-name: '📜 Documentation'
+name: "📜 Documentation"
-about: 'Correct spelling errors, improvements or additions to documentation files (README, CONTRIBUTING...).'
+about: "Correct spelling errors, improvements or additions to documentation files (README, CONTRIBUTING...)."
-title: '[Documentation]'
+title: "[Documentation]"
-labels: 'documentation'
+labels: "documentation"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/FEATURE_REQUEST.md

@@ -1,8 +1,8 @@
 ---
-name: '✨ Feature Request'
+name: "✨ Feature Request"
-about: 'Suggest a new feature idea.'
+about: "Suggest a new feature idea."
-title: '[Feature]'
+title: "[Feature]"
-labels: 'feature request'
+labels: "feature request"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/IMPROVEMENT.md

@@ -1,8 +1,8 @@
 ---
-name: '🔧 Improvement'
+name: "🔧 Improvement"
-about: 'Improve structure/format/performance/refactor/tests of the code.'
+about: "Improve structure/format/performance/refactor/tests of the code."
-title: '[Improvement]'
+title: "[Improvement]"
-labels: 'improvement'
+labels: "improvement"
 ---
 
 <!-- Please make sure your issue has not already been fixed. -->

.github/ISSUE_TEMPLATE/QUESTION.md

@@ -1,8 +1,8 @@
 ---
-name: '🙋 Question'
+name: "🙋 Question"
-about: 'Further information is requested.'
+about: "Further information is requested."
-title: '[Question]'
+title: "[Question]"
-labels: 'question'
+labels: "question"
 ---
 
 ### Question

.github/workflows/lint.yml

@@ -1,4 +1,4 @@
-name: 'Lint'
+name: "Lint"
 
 on:
   push:
@@ -8,21 +8,22 @@ on:
 
 jobs:
   lint:
-    runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     steps:
-      - uses: 'actions/checkout@v3.5.2'
+      - uses: "actions/checkout@v4.1.1"
 
-      - name: 'Setup Node.js'
+      - name: "Setup Node.js"
-        uses: 'actions/setup-node@v3.6.0'
+        uses: "actions/setup-node@v4.0.1"
         with:
-          node-version: 'lts/*'
+          node-version: "lts/*"
-          cache: 'npm'
+          cache: "npm"
 
-      - name: 'Install dependencies'
+      - name: "Install dependencies"
-        run: 'npm clean-install'
+        run: "npm clean-install"
 
       - run: 'npm run lint:commit -- --to "${{ github.sha }}"'
-      - run: 'npm run lint:editorconfig'
+      - run: "npm run lint:editorconfig"
-      - run: 'npm run lint:markdown'
+      - run: "npm run lint:markdown"
-      - run: 'npm run lint:eslint'
+      - run: "npm run lint:eslint"
-      - run: 'npm run lint:prettier'
+      - run: "npm run lint:prettier"
+      - run: "npm run lint:javascript"

.github/workflows/release.yml

@@ -1,4 +1,4 @@
-name: 'Release'
+name: "Release"
 
 on:
   push:
@@ -6,32 +6,32 @@ on:
 
 jobs:
   release:
-    runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     permissions:
-      contents: 'write'
+      contents: "write"
-      issues: 'write'
+      issues: "write"
-      pull-requests: 'write'
+      pull-requests: "write"
-      id-token: 'write'
+      id-token: "write"
     steps:
-      - uses: 'actions/checkout@v3.5.2'
+      - uses: "actions/checkout@v4.1.1"
         with:
           fetch-depth: 0
           persist-credentials: false
 
-      - name: 'Setup Node.js'
+      - name: "Setup Node.js"
-        uses: 'actions/setup-node@v3.6.0'
+        uses: "actions/setup-node@v4.0.1"
         with:
-          node-version: 'lts/*'
+          node-version: "lts/*"
-          cache: 'npm'
+          cache: "npm"
 
-      - name: 'Install dependencies'
+      - name: "Install dependencies"
-        run: 'npm clean-install'
+        run: "npm clean-install"
 
-      - name: 'Verify the integrity of provenance attestations and registry signatures for installed dependencies'
+      - name: "Verify the integrity of provenance attestations and registry signatures for installed dependencies"
-        run: 'npm audit signatures'
+        run: "npm audit signatures"
 
-      - name: 'Release'
+      - name: "Release"
-        run: 'npm run release'
+        run: "npm run release"
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/test.yml

@@ -1,4 +1,4 @@
-name: 'Test'
+name: "Test"
 
 on:
   push:
@@ -8,18 +8,18 @@ on:
 
 jobs:
   test:
-    runs-on: 'ubuntu-latest'
+    runs-on: "ubuntu-latest"
     steps:
-      - uses: 'actions/checkout@v3.5.2'
+      - uses: "actions/checkout@v4.1.1"
 
-      - name: 'Setup Node.js'
+      - name: "Setup Node.js"
-        uses: 'actions/setup-node@v3.6.0'
+        uses: "actions/setup-node@v4.0.1"
         with:
-          node-version: 'lts/*'
+          node-version: "lts/*"
-          cache: 'npm'
+          cache: "npm"
 
-      - name: 'Install dependencies'
+      - name: "Install dependencies"
-        run: 'npm clean-install'
+        run: "npm clean-install"
 
-      - name: 'Test'
+      - name: "Test"
-        run: 'npm run test'
+        run: "npm run test"

.husky/pre-commit

@@ -2,4 +2,5 @@
 . "$(dirname "$0")/_/husky.sh"
 
 npm run lint:staged
+npm run lint:javascript
 npm run test

.markdownlint-cli2.jsonc

@@ -1,11 +1,11 @@
 {
   "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"],
+  "ignores": ["**/node_modules", "**/test/fixtures/**"],
   "customRules": ["./src/index.js"]
 }

.prettierrc.json

@@ -1,6 +1,3 @@
 {
-  "singleQuote": true,
+  "semi": false
-  "jsxSingleQuote": true,
-  "semi": false,
-  "trailingComma": "none"
 }

.vscode/settings.json

@@ -3,6 +3,6 @@
   "prettier.configPath": ".prettierrc.json",
   "editor.formatOnSave": true,
   "editor.codeActionsOnSave": {
-    "source.fixAll": true
+    "source.fixAll": "explicit"
   }
 }

LICENSE

@@ -1,4 +1,4 @@
-MIT License
+# MIT License
 
 Copyright (c) Théo LUDWIG
 

README.md

@@ -5,12 +5,12 @@
 </p>
 
 <p align="center">
-  <a href="./CONTRIBUTING.md"><img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat" /></a>
+  <a href="./CONTRIBUTING.md"><img src="https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat" alt="CONTRIBUTING" /></a>
   <a href="./LICENSE"><img src="https://img.shields.io/badge/licence-MIT-blue.svg" alt="Licence MIT"/></a>
   <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" /></a>
+  <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" /></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>
@@ -43,9 +43,21 @@ With `awesome.md` content:
 Running [markdownlint-cli2](https://github.com/DavidAnson/markdownlint-cli2) with `markdownlint-rule-relative-links` will output:
 
 ```sh
-awesome.md:3 relative-links Relative links should be valid [Link "./invalid.txt" should exist in the file system]
+awesome.md:3 relative-links Relative links should be valid ["./invalid.txt" should exist in the file system]
 ```
 
+### Additional features
+
+- Support images (e.g: `![Image](./image.png)`).
+- 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 validated, html syntax is ignored (e.g: `<a href="./link.txt" />` or `<img src="./image.png" />`).
+
+Contributions are welcome to improve the rule, and to alleviate these limitations. See [CONTRIBUTING.md](./CONTRIBUTING.md) for more information.
+
 ### Related links
 
 - [DavidAnson/markdownlint#253](https://github.com/DavidAnson/markdownlint/issues/253)

jsconfig.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "lib": ["ESNext"],
+    "target": "ESNext",
+    "module": "CommonJS",
+    "moduleResolution": "Node",
+    "checkJs": true,
+    "allowJs": true,
+    "noEmit": true,
+    "rootDir": ".",
+    "baseUrl": ".",
+    "skipLibCheck": true,
+    "strict": true,
+    "allowUnusedLabels": false,
+    "allowUnreachableCode": false,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitAny": true,
+    "noImplicitOverride": true,
+    "noImplicitReturns": true,
+    "noUncheckedIndexedAccess": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "forceConsistentCasingInFileNames": true
+  }
+}

package.json

@@ -33,36 +33,39 @@
     "lint:commit": "commitlint",
     "lint:editorconfig": "editorconfig-checker",
     "lint:markdown": "markdownlint-cli2",
-    "lint:eslint": "eslint . --ignore-path .gitignore",
+    "lint:eslint": "eslint . --max-warnings 0 --report-unused-disable-directives --ignore-path .gitignore",
     "lint:prettier": "prettier . --check --ignore-path .gitignore",
+    "lint:javascript": "tsc --project jsconfig.json --noEmit",
     "lint:staged": "lint-staged",
-    "test": "node --test ./test",
+    "test": "node --test --experimental-test-coverage",
     "release": "semantic-release",
     "postinstall": "husky install",
     "prepublishOnly": "pinst --disable",
     "postpublish": "pinst --enable"
   },
   "dependencies": {
-    "markdown-it": "13.0.1"
+    "markdown-it": "14.0.0"
   },
   "devDependencies": {
-    "@commitlint/cli": "17.6.5",
+    "@commitlint/cli": "18.4.4",
-    "@commitlint/config-conventional": "17.6.5",
+    "@commitlint/config-conventional": "18.4.4",
-    "@types/node": "20.3.1",
+    "@types/markdown-it": "13.0.7",
-    "editorconfig-checker": "5.0.1",
+    "@types/node": "20.11.0",
-    "eslint": "8.43.0",
+    "editorconfig-checker": "5.1.2",
-    "eslint-config-conventions": "9.0.0",
+    "eslint": "8.56.0",
-    "eslint-config-prettier": "8.8.0",
+    "eslint-config-conventions": "13.1.0",
-    "eslint-plugin-import": "2.27.5",
+    "eslint-config-prettier": "9.1.0",
-    "eslint-plugin-prettier": "4.2.1",
+    "eslint-plugin-import": "2.29.1",
+    "eslint-plugin-prettier": "5.1.3",
     "eslint-plugin-promise": "6.1.1",
-    "eslint-plugin-unicorn": "47.0.0",
+    "eslint-plugin-unicorn": "50.0.1",
     "husky": "8.0.3",
-    "lint-staged": "13.2.2",
+    "lint-staged": "15.2.0",
-    "markdownlint": "0.29.0",
+    "markdownlint": "0.33.0",
-    "markdownlint-cli2": "0.8.1",
+    "markdownlint-cli2": "0.11.0",
     "pinst": "3.0.0",
-    "prettier": "2.8.8",
+    "prettier": "3.1.1",
-    "semantic-release": "21.0.5"
+    "semantic-release": "22.0.12",
+    "typescript": "5.3.3"
   }
 }

src/index.js

@@ -1,89 +1,132 @@
-'use strict'
+"use strict"
 
-const { pathToFileURL } = require('node:url')
+const { pathToFileURL } = require("node:url")
-const fs = require('node:fs')
+const fs = require("node:fs")
 
+const { filterTokens } = require("./markdownlint-rule-helpers/helpers.js")
 const {
-  filterTokens,
-  addError,
   convertHeadingToHTMLFragment,
-  getMarkdownHeadings
+  getMarkdownHeadings,
-} = require('./utils.js')
+  getMarkdownIdOrAnchorNameFragments,
+} = require("./utils.js")
 
+/** @typedef {import('markdownlint').Rule} MarkdownLintRule */
+
+/**
+ * @type {MarkdownLintRule}
+ */
 const customRule = {
-  names: ['relative-links'],
+  names: ["relative-links"],
-  description: 'Relative links should be valid',
+  description: "Relative links should be valid",
-  tags: ['links'],
+  tags: ["links"],
   function: (params, onError) => {
-    filterTokens(params, 'inline', (token) => {
+    filterTokens(params, "inline", (token) => {
-      token.children.forEach((child) => {
+      const children = token.children ?? []
-        const { lineNumber, type, attrs } = child
+      for (const child of children) {
+        const { type, attrs, lineNumber } = child
 
-        /** @type {string | null} */
+        /** @type {string | undefined} */
-        let hrefSrc = null
+        let hrefSrc
 
-        if (type === 'link_open') {
+        if (type === "link_open") {
-          attrs.forEach((attr) => {
+          for (const attr of attrs) {
-            if (attr[0] === 'href') {
+            if (attr[0] === "href") {
               hrefSrc = attr[1]
-            }
+              break
-          })
-        }
-
-        if (type === 'image') {
-          attrs.forEach((attr) => {
-            if (attr[0] === 'src') {
-              hrefSrc = attr[1]
-            }
-          })
-        }
-
-        if (hrefSrc != null) {
-          const url = new URL(hrefSrc, pathToFileURL(params.name))
-          const isRelative =
-            url.protocol === 'file:' && !hrefSrc.startsWith('/')
-          if (isRelative) {
-            const detail = `Link "${hrefSrc}"`
-
-            if (!fs.existsSync(url)) {
-              addError(
-                onError,
-                lineNumber,
-                `${detail} should exist in the file system`
-              )
-              return
-            }
-
-            if (type === 'link_open' && url.hash !== '') {
-              const fileContent = fs.readFileSync(url, { encoding: 'utf8' })
-              const headings = getMarkdownHeadings(fileContent)
-
-              /** @type {Map<string, number>} */
-              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)) {
-                addError(
-                  onError,
-                  lineNumber,
-                  `${detail} should have a valid fragment`
-                )
-              }
             }
           }
         }
-      })
+
+        if (type === "image") {
+          for (const attr of attrs) {
+            if (attr[0] === "src") {
+              hrefSrc = attr[1]
+              break
+            }
+          }
+        }
+
+        if (hrefSrc == null) {
+          continue
+        }
+
+        const url = new URL(hrefSrc, pathToFileURL(params.name))
+        const isRelative =
+          url.protocol === "file:" &&
+          !hrefSrc.startsWith("/") &&
+          !hrefSrc.startsWith("#")
+
+        if (!isRelative) {
+          continue
+        }
+
+        const detail = `"${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 not have a fragment identifier as it is an image`,
+              })
+              continue
+            }
+
+            onError({
+              lineNumber,
+              detail: `${detail} should have a valid fragment identifier`,
+            })
+            continue
+          }
+          continue
+        }
+
+        if (type !== "link_open") {
+          onError({
+            lineNumber,
+            detail: `${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
+        }
+      }
     })
-  }
+  },
 }
 
 module.exports = customRule

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

@@ -1,41 +1,6 @@
-const MarkdownIt = require('markdown-it')
+const MarkdownIt = require("markdown-it")
 
-/**
+const { getHtmlAttributeRe } = require("./markdownlint-rule-helpers/helpers.js")
- * Calls the provided function for each matching token.
- *
- * @param {Object} params RuleParams instance.
- * @param {string} type Token type identifier.
- * @param {Function} handler Callback function.
- * @returns {void}
- */
-const filterTokens = (params, type, handler) => {
-  for (const token of params.tokens) {
-    if (token.type === type) {
-      handler(token)
-    }
-  }
-}
-
-/**
- * Adds a generic error object via the onError callback.
- *
- * @param {Object} onError RuleOnError instance.
- * @param {number} lineNumber Line number.
- * @param {string} [detail] Error details.
- * @param {string} [context] Error context.
- * @param {number[]} [range] Column and length of error.
- * @param {Object} [fixInfo] RuleOnErrorFixInfo instance.
- * @returns {void}
- */
-const addError = (onError, lineNumber, detail, context, range, fixInfo) => {
-  onError({
-    lineNumber,
-    detail,
-    context,
-    range,
-    fixInfo
-  })
-}
 
 /**
  * Converts a Markdown heading into an HTML fragment according to the rules
@@ -47,25 +12,24 @@ const addError = (onError, lineNumber, detail, context, range, fixInfo) => {
  */
 const convertHeadingToHTMLFragment = (inlineText) => {
   return (
-    '#' +
+    "#" +
     encodeURIComponent(
       inlineText
         .toLowerCase()
         // RegExp source with Ruby's \p{Word} expanded into its General Categories
-        // eslint-disable-next-line max-len
         // https://github.com/gjtorikian/html-pipeline/blob/main/lib/html/pipeline/toc_filter.rb
         // https://ruby-doc.org/core-3.0.2/Regexp.html
         .replace(
           /[^\p{Letter}\p{Mark}\p{Number}\p{Connector_Punctuation}\- ]/gu,
-          ''
+          "",
         )
-        .replace(/ /gu, '-')
+        .replace(/ /gu, "-"),
     )
   )
 }
 
-const headingTags = new Set(['h1', 'h2', 'h3', 'h4', 'h5', 'h6'])
+const headingTags = new Set(["h1", "h2", "h3", "h4", "h5", "h6"])
-const ignoredTokens = new Set(['heading_open', 'heading_close'])
+const ignoredTokens = new Set(["heading_open", "heading_close"])
 
 /**
  * Gets the headings from a Markdown string.
@@ -84,9 +48,9 @@ const getMarkdownHeadings = (content) => {
 
   for (const token of tokens) {
     if (headingTags.has(token.tag)) {
-      if (token.type === 'heading_open') {
+      if (token.type === "heading_open") {
         headingToken = token.markup
-      } else if (token.type === 'heading_close') {
+      } else if (token.type === "heading_close") {
         headingToken = null
       }
     }
@@ -99,21 +63,59 @@ const getMarkdownHeadings = (content) => {
       continue
     }
 
+    const children = token.children ?? []
+
     headings.push(
-      `${token.children
+      `${children
         .map((token) => {
           return token.content
         })
-        .join('')}`
+        .join("")}`,
     )
   }
 
   return headings
 }
 
-module.exports = {
+const nameHTMLAttributeRegex = getHtmlAttributeRe("name")
-  filterTokens,
+const idHTMLAttributeRegex = getHtmlAttributeRe("id")
-  addError,
+
-  convertHeadingToHTMLFragment,
+/**
-  getMarkdownHeadings
+ * 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 = {
+  convertHeadingToHTMLFragment,
+  getMarkdownHeadings,
+  getMarkdownIdOrAnchorNameFragments,
 }

test/basic.test.js

@@ -1,46 +0,0 @@
-const test = require('node:test')
-const assert = require('node:assert/strict')
-
-const { markdownlint } = require('markdownlint').promises
-
-const relativeLinks = require('../src/index.js')
-
-test('ensure the rule validate correctly', async () => {
-  const lintResults = await markdownlint({
-    files: ['test/fixtures/Valid.md', 'test/fixtures/Invalid.md'],
-    config: {
-      default: false,
-      'relative-links': true
-    },
-    customRules: [relativeLinks]
-  })
-  assert.equal(lintResults['test/fixtures/Valid.md'].length, 0)
-  assert.equal(lintResults['test/fixtures/Invalid.md'].length, 3)
-
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][0]?.ruleDescription,
-    'Relative links should be valid'
-  )
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][0]?.errorDetail,
-    'Link "./basic.test.js" should exist in the file system'
-  )
-
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][1]?.ruleDescription,
-    'Relative links should be valid'
-  )
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][1]?.errorDetail,
-    'Link "../image.png" should exist in the file system'
-  )
-
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][2]?.ruleDescription,
-    'Relative links should be valid'
-  )
-  assert.equal(
-    lintResults['test/fixtures/Invalid.md'][2]?.errorDetail,
-    'Link "./Valid.md#not-existing-heading" should have a valid fragment'
-  )
-})

test/fixtures/Invalid.md

@@ -1,19 +0,0 @@
-# Invalid
-
-[basic.js](./basic.test.js)
-
-![Image](../image.png)
-
-[Link fragment](./Valid.md#not-existing-heading)
-
-## Existing Heading
-
-### Repeated Heading
-
-Text
-
-### Repeated Heading
-
-Text
-
-### Repeated Heading

test/fixtures/Valid.md

@@ -1,21 +0,0 @@
-# Valid
-
-[basic.js](../basic.test.js)
-
-![Image](./image.png)
-
-![Absolute Path](/absolute/path.png)
-
-[External https link](https://example.com/)
-
-[External https link 2](https:./external.https)
-
-[External ftp link](ftp:./external.ftp)
-
-[Link fragment](./Invalid.md#existing-heading)
-
-[Link fragment Repeated 0](./Invalid.md#repeated-heading)
-
-[Link fragment Repeated 1](./Invalid.md#repeated-heading-1)
-
-[Link fragment Repeated 2](./Invalid.md#repeated-heading-2)

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-file.md

@@ -0,0 +1,3 @@
+# Invalid
+
+[File](./index.test.js)

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

@@ -0,0 +1,3 @@
+# Awesome
+
+## Existing Heading

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

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

test/fixtures/invalid/non-existing-image.md

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

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-file.md

@@ -0,0 +1,3 @@
+# Valid
+
+[File](../../index.test.js)

test/fixtures/valid/existing-heading-fragment/awesome.md

@@ -0,0 +1,13 @@
+# Valid
+
+## Existing Heading
+
+### Repeated Heading
+
+Text
+
+### Repeated Heading
+
+Text
+
+### Repeated Heading

test/fixtures/valid/existing-heading-fragment/existing-heading-fragment.md

@@ -0,0 +1,9 @@
+# Valid
+
+[Link fragment](./awesome.md#existing-heading)
+
+[Link fragment Repeated 0](./awesome.md#repeated-heading)
+
+[Link fragment Repeated 1](./awesome.md#repeated-heading-1)
+
+[Link fragment Repeated 2](./awesome.md#repeated-heading-2)

test/fixtures/valid/existing-image.md

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

test/fixtures/valid/ignore-absolute-paths.md

@@ -0,0 +1,3 @@
+# Valid
+
+![Absolute Path](/absolute/path.png)

test/fixtures/valid/ignore-external-links.md

@@ -0,0 +1,7 @@
+# Valid
+
+[External https link](https://example.com/)
+
+[External https link 2](https:./external.https)
+
+[External ftp link](ftp:./external.ftp)

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

@@ -0,0 +1,156 @@
+const { test } = require("node:test")
+const assert = require("node:assert/strict")
+
+const { markdownlint } = require("markdownlint").promises
+
+const relativeLinksRule = require("../src/index.js")
+
+/**
+ *
+ * @param {string} fixtureFile
+ * @returns
+ */
+const validateMarkdownLint = async (fixtureFile) => {
+  const lintResults = await markdownlint({
+    files: [fixtureFile],
+    config: {
+      default: false,
+      "relative-links": true,
+    },
+    customRules: [relativeLinksRule],
+  })
+  return lintResults[fixtureFile]
+}
+
+test("ensure the rule validates correctly", async (t) => {
+  await t.test("should be invalid", async (t) => {
+    const testCases = [
+      {
+        name: "with an empty id fragment",
+        fixturePath:
+          "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',
+      },
+    ]
+
+    for (const { name, fixturePath, error } of testCases) {
+      await t.test(name, async () => {
+        const lintResults = await validateMarkdownLint(fixturePath)
+        assert.equal(lintResults?.length, 1)
+        assert.deepEqual(lintResults?.[0]?.ruleNames, relativeLinksRule.names)
+        assert.equal(
+          lintResults?.[0]?.ruleDescription,
+          relativeLinksRule.description,
+        )
+        assert.equal(lintResults?.[0]?.errorDetail, error)
+      })
+    }
+  })
+
+  await t.test("should be valid", async (t) => {
+    const testCases = [
+      {
+        name: "with an existing anchor name fragment",
+        fixturePath:
+          "test/fixtures/valid/existing-anchor-name-fragment/existing-anchor-name-fragment.md",
+      },
+      {
+        name: "with an existing element id fragment",
+        fixturePath:
+          "test/fixtures/valid/existing-element-id-fragment/existing-element-id-fragment.md",
+      },
+      {
+        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",
+      },
+    ]
+
+    for (const { name, fixturePath } of testCases) {
+      await t.test(name, async () => {
+        const lintResults = await validateMarkdownLint(fixturePath)
+        assert.equal(lintResults?.length, 0)
+      })
+    }
+  })
+})

test/utils.test.js

@@ -1,37 +1,57 @@
-const test = require('node:test')
+const { test } = require("node:test")
-const assert = require('node:assert/strict')
+const assert = require("node:assert/strict")
 
 const {
   convertHeadingToHTMLFragment,
-  getMarkdownHeadings
+  getMarkdownHeadings,
-} = require('../src/utils.js')
+  getMarkdownIdOrAnchorNameFragments,
+} = require("../src/utils.js")
 
-test('utils', async (t) => {
+test("utils", async (t) => {
-  await t.test('convertHeadingToHTMLFragment', async () => {
+  await t.test("convertHeadingToHTMLFragment", async () => {
     assert.strictEqual(
-      convertHeadingToHTMLFragment('Valid Fragments'),
+      convertHeadingToHTMLFragment("Valid Fragments"),
-      '#valid-fragments'
+      "#valid-fragments",
     )
     assert.strictEqual(
-      convertHeadingToHTMLFragment('Valid Heading With Underscores _'),
+      convertHeadingToHTMLFragment("Valid Heading With Underscores _"),
-      '#valid-heading-with-underscores-_'
+      "#valid-heading-with-underscores-_",
     )
     assert.strictEqual(
       convertHeadingToHTMLFragment(
-        `Valid Heading With Quotes ' And Double Quotes "`
+        `Valid Heading With Quotes ' And Double Quotes "`,
       ),
-      '#valid-heading-with-quotes--and-double-quotes-'
+      "#valid-heading-with-quotes--and-double-quotes-",
     )
     assert.strictEqual(
-      convertHeadingToHTMLFragment('🚀 Valid Heading With Emoji'),
+      convertHeadingToHTMLFragment("🚀 Valid Heading With Emoji"),
-      '#-valid-heading-with-emoji'
+      "#-valid-heading-with-emoji",
     )
   })
 
-  await t.test('getMarkdownHeadings', async () => {
+  await t.test("getMarkdownHeadings", async () => {
     assert.deepStrictEqual(
-      getMarkdownHeadings('# Hello\n\n## World\n\n## Hello, world!\n'),
+      getMarkdownHeadings("# Hello\n\n## World\n\n## Hello, world!\n"),
-      ['Hello', 'World', 'Hello, world!']
+      ["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=>"), [])
+  })
 })