fix: unescape H1 markdown

Author: mnaoumov

__tests__/yaml-title.test.ts

@@ -374,5 +374,17 @@ ruleTest({
         # Hello world
       `,
     },
+    { // accounts for https://github.com/platers/obsidian-linter/issues/1428
+      testName: 'Unescapes H1 markdown special characters',
+      before: dedent`
+        # Escape \\[\\_\\]
+      `,
+      after: dedent`
+        ---
+        title: Escape [_]
+        ---
+        # Escape \\[\\_\\]
+      `,
+    },
   ],
 });

src/utils/regex.ts

@@ -1,5 +1,5 @@
 import {getAllTablesInText} from './mdast';
-import {makeSureContentHasEmptyLinesAddedBeforeAndAfter} from './strings';
+import {makeSureContentHasEmptyLinesAddedBeforeAndAfter, unescapeMarkdownSpecialCharacters} from './strings';
 
 // Useful regexes
 export const allHeadersRegex = /^([ \t]*)(#+)([ \t]+)([^\n\r]*?)([ \t]+#+)?$/gm;
@@ -123,7 +123,8 @@ export function getFirstHeaderOneText(text: string): string {
       return $2;
     });
 
-    return headerText.replaceAll(genericLinkRegex, '$2');
+    headerText = headerText.replaceAll(genericLinkRegex, '$2');
+    return unescapeMarkdownSpecialCharacters(headerText);
   }
 
   return '';

src/utils/strings.ts

@@ -1,7 +1,7 @@
-import {calloutRegex, codeBlockBlockquoteRegex} from './regex';
-import {getTextInLanguage} from '../lang/helpers';
-import {logWarn} from './logger';
-import {getAllTablesInText} from './mdast';
+import { calloutRegex, codeBlockBlockquoteRegex } from './regex';
+import { getTextInLanguage } from '../lang/helpers';
+import { logWarn } from './logger';
+import { getAllTablesInText } from './mdast';
 /**
  * Inserts a string at the given position in a string.
  * @param {string} str - The string to insert into
@@ -163,7 +163,7 @@ function makeSureContentHasASingleEmptyLineBeforeItUnlessItStartsAFileForBlockqu
   }
 
   let firstLineOfBlockquote: string;
-  const indexOfEndOfFirstLine = text.indexOf('\n', startOfContent+1);
+  const indexOfEndOfFirstLine = text.indexOf('\n', startOfContent + 1);
   if (indexOfEndOfFirstLine === -1) {
     firstLineOfBlockquote = text.substring(startOfContent);
   } else {
@@ -289,11 +289,11 @@ function makeSureContentHasASingleEmptyLineAfterItUnlessItEndsAFileForBlockquote
   }
 
   let lastLineOfBlockquote: string;
-  const indexOfEndOfLastLine = text.lastIndexOf('\n', endOfContent-1);
+  const indexOfEndOfLastLine = text.lastIndexOf('\n', endOfContent - 1);
   if (indexOfEndOfLastLine === -1) {
     lastLineOfBlockquote = text.substring(0, endOfNewContent);
   } else {
-    lastLineOfBlockquote = text.substring(indexOfEndOfLastLine+1, endOfContent);
+    lastLineOfBlockquote = text.substring(indexOfEndOfLastLine + 1, endOfContent);
   }
 
   let emptyLine: string;
@@ -408,7 +408,7 @@ export function replaceAt(text: string, search: string, replace: string, start:
   }
 
   return text.slice(0, start) +
-      text.slice(start, text.length).replace(search, replace);
+    text.slice(start, text.length).replace(search, replace);
 }
 
 // based on https://stackoverflow.com/a/21730166/8353749
@@ -432,7 +432,7 @@ export function isNumeric(str: string) {
   const type = typeof str;
   if (type != 'string') return type === 'number'; // we only process strings so if the value is not already a number the result is false
   return !isNaN(str as unknown as number) && // use type coercion to parse the _entirety_ of the string (`parseFloat` alone does not do this)...
-         !isNaN(parseFloat(str)); // ...and ensure strings of whitespace fail
+    !isNaN(parseFloat(str)); // ...and ensure strings of whitespace fail
 }
 
 export function getSubstringIndex(substring: string, text: string): number[] {
@@ -447,7 +447,7 @@ export function getSubstringIndex(substring: string, text: string): number[] {
 
 function getIndexOfStartOfFirstNonEmptyLine(text: string, currentStartOfBlockquote: number, blockquoteLevel: number): number {
   let actualStartOfBlockquote = currentStartOfBlockquote;
-  let blockquoteIndex = currentStartOfBlockquote+1;
+  let blockquoteIndex = currentStartOfBlockquote + 1;
   let currentChar = '';
   let foundNewStart = false;
   let level = 0;
@@ -479,7 +479,7 @@ function getIndexOfStartOfFirstNonEmptyLine(text: string, currentStartOfBlockquo
 
 function getIndexOfEndOfLastNonEmptyLine(text: string, currentEndOfBlockquote: number, blockquoteLevel: number): number {
   let actualEndOfBlockquote = currentEndOfBlockquote;
-  let blockquoteIndex = currentEndOfBlockquote-1;
+  let blockquoteIndex = currentEndOfBlockquote - 1;
   let currentChar = '';
   let foundNewEnd = false;
   let level = 0;
@@ -535,3 +535,22 @@ export function parseCustomReplacements(text: string): Map<string, string> {
 
   return customReplacements;
 }
+
+/**
+ * Unescapes the markdown special characters in the provided text.
+ *
+ * @param {string} text - The text to unescape the markdown special characters in.
+ * @return {string} The text with the markdown special characters unescaped.
+ * 
+ * @example
+ * ```ts
+ * unescapeMarkdownSpecialCharacters('Escape \\[\\_\\]'); // Escape [_]
+ * ```
+ */
+export function unescapeMarkdownSpecialCharacters(text: string): string {
+  return text.replace(/(\\+)([!"#$%&'()*+,-./:;<=>?@\[\\\]^_`{|}~])/g, (_, backslashes, specialChar) => {
+    const backslashCount = backslashes.length;
+    const keepCount = Math.floor(backslashCount / 2);
+    return '\\'.repeat(keepCount) + specialChar;
+  });
+}