Update MD043/required-headings to add match_case parameter (fixes #613).

demo/markdownlint-browser.js

@@ -4297,6 +4297,7 @@ module.exports = {
     "tags": ["headings", "headers"],
     "function": function MD043(params, onError) {
         const requiredHeadings = params.config.headings || params.config.headers;
+        const matchCase = params.config.match_case || false;
         if (Array.isArray(requiredHeadings)) {
             const levels = {};
             for (const level of [1, 2, 3, 4, 5, 6]) {
@@ -4307,6 +4308,7 @@ module.exports = {
             let hasError = false;
             let anyHeadings = false;
             const getExpected = () => requiredHeadings[i++] || "[None]";
+            const handleCase = (str) => (matchCase ? str : str.toLowerCase());
             forEachHeading(params, (heading, content) => {
                 if (!hasError) {
                     anyHeadings = true;
@@ -4314,7 +4316,7 @@ module.exports = {
                     const expected = getExpected();
                     if (expected === "*") {
                         const nextExpected = getExpected();
-                        if (nextExpected.toLowerCase() !== actual.toLowerCase()) {
+                        if (handleCase(nextExpected) !== handleCase(actual)) {
                             matchAny = true;
                             i--;
                         }
@@ -4322,7 +4324,7 @@ module.exports = {
                     else if (expected === "+") {
                         matchAny = true;
                     }
-                    else if (expected.toLowerCase() === actual.toLowerCase()) {
+                    else if (handleCase(expected) === handleCase(actual)) {
                         matchAny = false;
                     }
                     else if (matchAny) {

doc/Rules.md

@@ -1696,7 +1696,7 @@ Tags: headings, headers
 
 Aliases: required-headings, required-headers
 
-Parameters: headings, headers (array of string; default `null` for disabled)
+Parameters: headings, headers, match_case (array of string; default `null` for disabled, boolean; default false)
 
 > If `headings` is not provided, `headers` (deprecated) will be used.
 
@@ -1752,6 +1752,10 @@ problematic heading (otherwise, it outputs the last line number of the file).
 Note that while the `headings` parameter uses the "## Text" ATX heading style for
 simplicity, a file may use any supported heading style.
 
+By default, the case of headings in the document is not required to match that of
+`headings`. To require that case match exactly, set the `match_case` parameter to
+`true`.
+
 Rationale: Projects may wish to enforce a consistent document structure across
 a set of similar content.
 

lib/md043.js

@@ -11,6 +11,7 @@ module.exports = {
   "tags": [ "headings", "headers" ],
   "function": function MD043(params, onError) {
     const requiredHeadings = params.config.headings || params.config.headers;
+    const matchCase = params.config.match_case || false;
     if (Array.isArray(requiredHeadings)) {
       const levels = {};
       for (const level of [ 1, 2, 3, 4, 5, 6 ]) {
@@ -21,6 +22,7 @@ module.exports = {
       let hasError = false;
       let anyHeadings = false;
       const getExpected = () => requiredHeadings[i++] || "[None]";
+      const handleCase = (str) => (matchCase ? str : str.toLowerCase());
       forEachHeading(params, (heading, content) => {
         if (!hasError) {
           anyHeadings = true;
@@ -28,13 +30,13 @@ module.exports = {
           const expected = getExpected();
           if (expected === "*") {
             const nextExpected = getExpected();
-            if (nextExpected.toLowerCase() !== actual.toLowerCase()) {
+            if (handleCase(nextExpected) !== handleCase(actual)) {
               matchAny = true;
               i--;
             }
           } else if (expected === "+") {
             matchAny = true;
-          } else if (expected.toLowerCase() === actual.toLowerCase()) {
+          } else if (handleCase(expected) === handleCase(actual)) {
             matchAny = false;
           } else if (matchAny) {
             i--;

schema/.markdownlint.jsonc

@@ -228,7 +228,9 @@
     // List of headings
     "headings": [],
     // List of headings
-    "headers": []
+    "headers": [],
+    // Match case of headings
+    "match_case": false
   },
 
   // MD044/proper-names - Proper names should have the correct capitalization

schema/.markdownlint.yaml

@@ -208,6 +208,8 @@ MD043:
   headings: []
   # List of headings
   headers: []
+  # Match case of headings
+  match_case: false
 
 # MD044/proper-names - Proper names should have the correct capitalization
 MD044:

schema/build-config-schema.js

@@ -395,6 +395,11 @@ for (const rule of rules) {
             "pattern": "^(\\*|\\+|#{1,6} .*)$"
           },
           "default": []
+        },
+        "match_case": {
+          "description": "Match case of headings",
+          "type": "boolean",
+          "default": false
         }
       };
       break;

schema/markdownlint-config-schema.json

@@ -751,6 +751,11 @@
             "pattern": "^(\\*|\\+|#{1,6} .*)$"
           },
           "default": []
+        },
+        "match_case": {
+          "description": "Match case of headings",
+          "type": "boolean",
+          "default": false
         }
       },
       "additionalProperties": false

test/required-headings-match-case.json

@@ -0,0 +1,12 @@
+{
+  "MD043": {
+    "headings": [
+      "# Title",
+      "## First Heading",
+      "## Second Heading",
+      "*",
+      "## Third Heading"
+    ],
+    "match_case": true
+  }
+}

test/required-headings-match-case.md

@@ -0,0 +1,9 @@
+# Title
+
+## First Heading
+
+## Second Heading
+
+### Random heading
+
+## Third Heading

test/required-headings-wrong-match-case.json

@@ -0,0 +1,12 @@
+{
+  "MD043": {
+    "headings": [
+      "# Title",
+      "## First Heading",
+      "## Second Heading",
+      "*",
+      "## Third Heading"
+    ],
+    "match_case": true
+  }
+}

test/required-headings-wrong-match-case.md

@@ -0,0 +1,11 @@
+# Title
+
+## First Heading
+
+## SECOND HEADING
+
+{MD043:5}
+
+### Random heading
+
+## Third Heading

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

@@ -34838,6 +34838,24 @@ Generated by [AVA](https://avajs.dev).
       `,
     }
 
+## required-headings-match-case.md
+
+> Snapshot 1
+
+    {
+      errors: [],
+      fixed: `# Title␊
+      ␊
+      ## First Heading␊
+      ␊
+      ## Second Heading␊
+      ␊
+      ### Random heading␊
+      ␊
+      ## Third Heading␊
+      `,
+    }
+
 ## required-headings-missing-first.md
 
 > Snapshot 1
@@ -35216,6 +35234,41 @@ Generated by [AVA](https://avajs.dev).
       `,
     }
 
+## required-headings-wrong-match-case.md
+
+> Snapshot 1
+
+    {
+      errors: [
+        {
+          errorContext: null,
+          errorDetail: 'Expected: ## Second Heading; Actual: ## SECOND HEADING',
+          errorRange: null,
+          fixInfo: null,
+          lineNumber: 5,
+          ruleDescription: 'Required heading structure',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md043',
+          ruleNames: [
+            'MD043',
+            'required-headings',
+            'required-headers',
+          ],
+        },
+      ],
+      fixed: `# Title␊
+      ␊
+      ## First Heading␊
+      ␊
+      ## SECOND HEADING␊
+      ␊
+      {MD043:5}␊
+      ␊
+      ### Random heading␊
+      ␊
+      ## Third Heading␊
+      `,
+    }
+
 ## required-headings-zero-or-more-last.md
 
 > Snapshot 1