Update MD026/no-trailing-punctuation to handle empty punctuation paramater, escape for RegExp (fixes #205).

doc/Rules.md

@@ -792,23 +792,24 @@ Aliases: no-trailing-punctuation
 
 Parameters: punctuation (string; default ".,;:!?。，；：！？")
 
-This rule is triggered on any heading that has a normal or full-width punctuation
-character as the last character in the line:
+This rule is triggered on any heading that has one of the specified normal or
+full-width punctuation characters as the last character in the line:
 
 ```markdown
 # This is a heading.
 ```
 
-To fix this, remove any trailing punctuation:
+To fix this, remove the trailing punctuation:
 
 ```markdown
 # This is a heading
 ```
 
-Note: The punctuation parameter can be used to specify what characters class
-as punctuation at the end of the heading. For example, you can set it to
-`".,;:!"` to allow headings with question marks in them, such as might be used
-in an FAQ.
+Note: The `punctuation` parameter can be used to specify what characters count
+as punctuation at the end of a heading. For example, you can change it to
+`".,;:!"` to allow headings that end with a question mark, such as in an FAQ.
+Setting the `punctuation` parameter to `""` allows all characters - and is
+equivalent to disabling the rule.
 
 <a name="md027"></a>
 

lib/md026.js

@@ -2,17 +2,21 @@
 
 "use strict";
 
-const { addError, allPunctuation, forEachHeading, rangeFromRegExp } =
-  require("../helpers");
+const { addError, allPunctuation, escapeForRegExp, forEachHeading,
+  rangeFromRegExp } = require("../helpers");
 
 module.exports = {
   "names": [ "MD026", "no-trailing-punctuation" ],
   "description": "Trailing punctuation in heading",
   "tags": [ "headings", "headers" ],
   "function": function MD026(params, onError) {
-    const punctuation = params.config.punctuation || allPunctuation;
-    const trailingPunctuationRe = new RegExp("[" + punctuation + "]$");
-    forEachHeading(params, function forHeading(heading, content) {
+    let punctuation = params.config.punctuation;
+    if (punctuation === undefined) {
+      punctuation = allPunctuation;
+    }
+    const trailingPunctuationRe =
+      new RegExp("[" + escapeForRegExp(punctuation) + "]$");
+    forEachHeading(params, (heading, content) => {
       const match = trailingPunctuationRe.exec(content);
       if (match) {
         addError(onError, heading.lineNumber,

test/heading_trailing_punctuation_customized.json

@@ -1,6 +1,6 @@
 {
   "default": true,
   "MD026": {
-    "punctuation": ".,;:!"
+    "punctuation": ".,;:!]"
   }
 }

test/heading_trailing_punctuation_customized.md

@@ -10,5 +10,7 @@
 
 ## Heading 6?
 
+## Heading 7 {MD026}]
+
 The rule has been customized to allow question marks while disallowing
 everything else.

test/heading_trailing_punctuation_empty.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD026": {
+    "punctuation": ""
+  }
+}

test/heading_trailing_punctuation_empty.md

@@ -0,0 +1,13 @@
+# Heading Trailing Punctuation
+
+## Heading .
+
+## Heading ,
+
+## Heading ;
+
+## Heading :
+
+## Heading !
+
+## Heading ?