Reimplement MD024/no-duplicate-heading using micromark tokens.

demo/markdownlint-browser.js

@@ -1564,6 +1564,20 @@ function getHeadingStyle(heading) {
   return "atx_closed";
 }
 
+/**
+ * Gets the heading text of a Micromark heading token.
+ *
+ * @param {Token} heading Micromark heading token.
+ * @returns {string} Heading text.
+ */
+function getHeadingText(heading) {
+  const headingTexts = filterByTypes(
+    heading.children,
+    [ "atxHeadingText", "setextHeadingText" ]
+  );
+  return headingTexts[0]?.text.replace(/[\r\n]+/g, " ") || "";
+}
+
 /**
  * HTML tag information.
  *
@@ -1679,6 +1693,7 @@ module.exports = {
   filterByTypes,
   getHeadingLevel,
   getHeadingStyle,
+  getHeadingText,
   getHtmlTagInfo,
   getMicromarkEvents,
   getTokenParentOfType,
@@ -4575,7 +4590,8 @@ module.exports = {
 
 
 
-const { addErrorContext, forEachHeading } = __webpack_require__(/*! ../helpers */ "../helpers/helpers.js");
+const { addErrorContext } = __webpack_require__(/*! ../helpers */ "../helpers/helpers.js");
+const { filterByTypes, getHeadingLevel, getHeadingText } = __webpack_require__(/*! ../helpers/micromark.cjs */ "../helpers/micromark.cjs");
 
 // eslint-disable-next-line jsdoc/valid-types
 /** @type import("./markdownlint").Rule */
@@ -4583,15 +4599,20 @@ module.exports = {
   "names": [ "MD024", "no-duplicate-heading" ],
   "description": "Multiple headings with the same content",
   "tags": [ "headings" ],
-  "parser": "markdownit",
+  "parser": "micromark",
   "function": function MD024(params, onError) {
     const siblingsOnly = !!params.config.siblings_only || false;
     const knownContents = [ null, [] ];
     let lastLevel = 1;
     let knownContent = knownContents[lastLevel];
-    forEachHeading(params, (heading, content) => {
+    const headings = filterByTypes(
+      params.parsers.micromark.tokens,
+      [ "atxHeading", "setextHeading" ]
+    );
+    for (const heading of headings) {
+      const headingText = getHeadingText(heading);
       if (siblingsOnly) {
-        const newLevel = heading.tag.slice(1);
+        const newLevel = getHeadingLevel(heading);
         while (lastLevel < newLevel) {
           lastLevel++;
           knownContents[lastLevel] = [];
@@ -4603,17 +4624,17 @@ module.exports = {
         knownContent = knownContents[newLevel];
       }
       // @ts-ignore
-      if (knownContent.includes(content)) {
+      if (knownContent.includes(headingText)) {
         addErrorContext(
           onError,
-          heading.lineNumber,
-          heading.line.trim()
+          heading.startLine,
+          headingText.trim()
         );
       } else {
         // @ts-ignore
-        knownContent.push(content);
+        knownContent.push(headingText);
       }
-    });
+    }
   }
 };
 
@@ -4632,7 +4653,7 @@ module.exports = {
 
 
 const { addErrorContext, frontMatterHasTitle } = __webpack_require__(/*! ../helpers */ "../helpers/helpers.js");
-const { filterByTypes, getHeadingLevel } = __webpack_require__(/*! ../helpers/micromark.cjs */ "../helpers/micromark.cjs");
+const { filterByTypes, getHeadingLevel, getHeadingText } = __webpack_require__(/*! ../helpers/micromark.cjs */ "../helpers/micromark.cjs");
 
 // eslint-disable-next-line jsdoc/valid-types
 /** @type import("./markdownlint").Rule */
@@ -4657,14 +4678,7 @@ module.exports = {
       const headingLevel = getHeadingLevel(heading);
       if (headingLevel === level) {
         if (hasTopLevelHeading || foundFrontMatterTitle) {
-          const headingTexts = filterByTypes(
-            heading.children,
-            [ "atxHeadingText", "setextHeadingText" ]
-          );
-          const headingText = headingTexts.
-            map((token) => token.text).
-            join(" ").
-            replace(/[\r\n]+/g, " ");
+          const headingText = getHeadingText(heading);
           addErrorContext(
             onError,
             heading.startLine,

helpers/micromark.cjs

@@ -345,6 +345,20 @@ function getHeadingStyle(heading) {
   return "atx_closed";
 }
 
+/**
+ * Gets the heading text of a Micromark heading token.
+ *
+ * @param {Token} heading Micromark heading token.
+ * @returns {string} Heading text.
+ */
+function getHeadingText(heading) {
+  const headingTexts = filterByTypes(
+    heading.children,
+    [ "atxHeadingText", "setextHeadingText" ]
+  );
+  return headingTexts[0]?.text.replace(/[\r\n]+/g, " ") || "";
+}
+
 /**
  * HTML tag information.
  *
@@ -460,6 +474,7 @@ module.exports = {
   filterByTypes,
   getHeadingLevel,
   getHeadingStyle,
+  getHeadingText,
   getHtmlTagInfo,
   getMicromarkEvents,
   getTokenParentOfType,

lib/md024.js

@@ -2,7 +2,8 @@
 
 "use strict";
 
-const { addErrorContext, forEachHeading } = require("../helpers");
+const { addErrorContext } = require("../helpers");
+const { filterByTypes, getHeadingLevel, getHeadingText } = require("../helpers/micromark.cjs");
 
 // eslint-disable-next-line jsdoc/valid-types
 /** @type import("./markdownlint").Rule */
@@ -10,15 +11,20 @@ module.exports = {
   "names": [ "MD024", "no-duplicate-heading" ],
   "description": "Multiple headings with the same content",
   "tags": [ "headings" ],
-  "parser": "markdownit",
+  "parser": "micromark",
   "function": function MD024(params, onError) {
     const siblingsOnly = !!params.config.siblings_only || false;
     const knownContents = [ null, [] ];
     let lastLevel = 1;
     let knownContent = knownContents[lastLevel];
-    forEachHeading(params, (heading, content) => {
+    const headings = filterByTypes(
+      params.parsers.micromark.tokens,
+      [ "atxHeading", "setextHeading" ]
+    );
+    for (const heading of headings) {
+      const headingText = getHeadingText(heading);
       if (siblingsOnly) {
-        const newLevel = heading.tag.slice(1);
+        const newLevel = getHeadingLevel(heading);
         while (lastLevel < newLevel) {
           lastLevel++;
           knownContents[lastLevel] = [];
@@ -30,16 +36,16 @@ module.exports = {
         knownContent = knownContents[newLevel];
       }
       // @ts-ignore
-      if (knownContent.includes(content)) {
+      if (knownContent.includes(headingText)) {
         addErrorContext(
           onError,
-          heading.lineNumber,
-          heading.line.trim()
+          heading.startLine,
+          headingText.trim()
         );
       } else {
         // @ts-ignore
-        knownContent.push(content);
+        knownContent.push(headingText);
       }
-    });
+    }
   }
 };

lib/md025.js

@@ -3,7 +3,7 @@
 "use strict";
 
 const { addErrorContext, frontMatterHasTitle } = require("../helpers");
-const { filterByTypes, getHeadingLevel } = require("../helpers/micromark.cjs");
+const { filterByTypes, getHeadingLevel, getHeadingText } = require("../helpers/micromark.cjs");
 
 // eslint-disable-next-line jsdoc/valid-types
 /** @type import("./markdownlint").Rule */
@@ -28,14 +28,7 @@ module.exports = {
       const headingLevel = getHeadingLevel(heading);
       if (headingLevel === level) {
         if (hasTopLevelHeading || foundFrontMatterTitle) {
-          const headingTexts = filterByTypes(
-            heading.children,
-            [ "atxHeadingText", "setextHeadingText" ]
-          );
-          const headingText = headingTexts.
-            map((token) => token.text).
-            join(" ").
-            replace(/[\r\n]+/g, " ");
+          const headingText = getHeadingText(heading);
           addErrorContext(
             onError,
             heading.startLine,

test/snapshots/markdownlint-test-scenarios.js.md

@@ -638,7 +638,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '# Heading',
+          errorContext: 'Heading',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -7156,7 +7156,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '# Heading 8',
+          errorContext: 'Heading 8',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14804,7 +14804,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '## B',
+          errorContext: 'B',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14817,7 +14817,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '### C',
+          errorContext: 'C',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14830,7 +14830,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '#### G',
+          errorContext: 'G',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14843,7 +14843,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '### E',
+          errorContext: 'E',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14856,7 +14856,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '# A',
+          errorContext: 'A',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14869,7 +14869,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '## B',
+          errorContext: 'B',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14882,7 +14882,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '# Heading duplicate content si...',
+          errorContext: 'Heading duplicate content sibl...',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -14908,7 +14908,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '## BBB ##',
+          errorContext: 'BBB',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -15104,7 +15104,7 @@ Generated by [AVA](https://avajs.dev).
     {
       errors: [
         {
-          errorContext: '## Heading 1',
+          errorContext: 'Heading 1',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -15117,7 +15117,7 @@ Generated by [AVA](https://avajs.dev).
           ],
         },
         {
-          errorContext: '### Heading 2',
+          errorContext: 'Heading 2',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,
@@ -15177,7 +15177,7 @@ Generated by [AVA](https://avajs.dev).
     {
       errors: [
         {
-          errorContext: '### Bug fixes',
+          errorContext: 'Bug fixes',
           errorDetail: null,
           errorRange: null,
           fixInfo: null,