Reimplement MD026/no-trailing-punctuation using micromark tokens, ignore trailing GitHub emoji codes, improve tests (fixes #457).

lib/md026.js

@@ -2,10 +2,10 @@
 
 "use strict";
 
-const { addError, allPunctuationNoQuestion, escapeForRegExp, forEachHeading } =
-  require("../helpers");
+const { addError, allPunctuationNoQuestion, endOfLineGemojiCodeRe,
+  endOfLineHtmlEntityRe, escapeForRegExp } = require("../helpers");
+const { filterByTypes } = require("../helpers/micromark.cjs");
 
-const endOfLineHtmlEntityRe = /&#?[\da-zA-Z]+;$/;
 
 module.exports = {
   "names": [ "MD026", "no-trailing-punctuation" ],
@@ -18,19 +18,26 @@ module.exports = {
     );
     const trailingPunctuationRe =
       new RegExp("\\s*[" + escapeForRegExp(punctuation) + "]+$");
-    forEachHeading(params, (heading) => {
-      const { line, lineNumber } = heading;
-      const trimmedLine = line.replace(/([^\s#])[\s#]+$/, "$1");
-      const match = trailingPunctuationRe.exec(trimmedLine);
-      if (match && !endOfLineHtmlEntityRe.test(trimmedLine)) {
+    const headings = filterByTypes(
+      params.parsers.micromark.tokens,
+      [ "atxHeadingText", "setextHeadingText" ]
+    );
+    for (const heading of headings) {
+      const { endLine, startColumn, text } = heading;
+      const match = trailingPunctuationRe.exec(text);
+      if (
+        match &&
+        !endOfLineHtmlEntityRe.test(text) &&
+        !endOfLineGemojiCodeRe.test(text)
+      ) {
         const fullMatch = match[0];
-        const column = match.index + 1;
+        const column = startColumn + match.index;
         const length = fullMatch.length;
         addError(
           onError,
-          lineNumber,
+          endLine,
           `Punctuation: '${fullMatch}'`,
-          null,
+          undefined,
           [ column, length ],
           {
             "editColumn": column,
@@ -38,6 +45,6 @@ module.exports = {
           }
         );
       }
-    });
+    }
   }
 };