feat(anchors): remove unsupported chars from heading ids

package.json

@@ -59,7 +59,7 @@
     "markdownlint": "^0.32.1",
     "markdownlint-rule-helpers": "0.17.2",
     "sanitize-html": "^2.11.0",
-    "slugify": "1.6.5",
+    "slugify": "1.6.6",
     "svgo": "^3.2.0"
   },
   "devDependencies": {

src/transform/plugins/anchors/index.ts

@@ -3,14 +3,13 @@ import GithubSlugger from 'github-slugger';
 import StateCore from 'markdown-it/lib/rules_core/state_core';
 import Token from 'markdown-it/lib/token';
 import {escapeHtml} from 'markdown-it/lib/common/utils';
+import slugify from 'slugify';
 
 import {headingInfo} from '../../utils';
 import {MarkdownItPluginCb} from '../typings';
 
 import {CUSTOM_ID_EXCEPTION, CUSTOM_ID_REGEXP} from './constants';
 
-const slugify: (str: string, opts: {}) => string = require('slugify');
-
 function createLinkTokens(
     state: StateCore,
     id: string,
@@ -127,7 +126,7 @@ const index: MarkdownItPluginCb<Options> = (md, options) => {
                 } else {
                     id = slugify(title, {
                         lower: true,
-                        remove: /[*+~.()'"!:@`ь?]/g,
+                        remove: /[^\w\s$_\-,;=/]+/g,
                     });
                     ghId = slugger.slug(title);
                 }

test/__snapshots__/anchors.test.ts.snap

@@ -29,6 +29,25 @@ exports[`Anchors should add anchor with auto naming, using entire heading text 1
 </p>
 `;
 
+exports[`Anchors should add id for heading with allowed chars in fragment (RFC 3986)  1`] = `
+<h2 id="a-c5percentdollarandabc_;xx,=3/bbb">
+  <a href="link.html#a-c5percentdollarandabc_;xx,=3/bbb"
+     class="yfm-anchor"
+     aria-hidden="true"
+  >
+    <span class="visually-hidden"
+          data-no-index="true"
+    >
+      A-c~5%!$&amp;(abc)*_+;xx,@=3/':b?b.b'
+    </span>
+  </a>
+  A-c~5%!$&amp;(abc)*_+;xx,@=3/':b?b.b'
+</h2>
+<p>
+  Content
+</p>
+`;
+
 exports[`Anchors should add multiple anchors 1`] = `
 <pre>
   <code>
@@ -234,6 +253,25 @@ exports[`Anchors should include content by anchor in sharped path file 1`] = `
 </p>
 `;
 
+exports[`Anchors should remove quotes from id 1`] = `
+<h2 id="heading-with-quotes">
+  <a href="link.html#heading-with-quotes"
+     class="yfm-anchor"
+     aria-hidden="true"
+  >
+    <span class="visually-hidden"
+          data-no-index="true"
+    >
+      «Heading» “with” "quotes'
+    </span>
+  </a>
+  «Heading» “with” "quotes'
+</h2>
+<p>
+  Content
+</p>
+`;
+
 exports[`Anchors with extract title should not add an anchor for level 1 heading 1`] = `
 <p>
   Content

test/anchors.test.ts

@@ -121,6 +121,28 @@ describe('Anchors', () => {
         ).toMatchSnapshot();
     });
 
+    it('should add id for heading with allowed chars in fragment (RFC 3986) ', () => {
+        expect(
+            // heading contains all allowed chars in fragment (hash) in accordance with RFC 3986
+            html(dedent`
+                ## A-c~5%!$&(abc)*_+;xx,@=3/':b?b.b'
+
+                Content
+                `),
+        ).toMatchSnapshot();
+    });
+
+    it('should remove quotes from id', () => {
+        expect(
+            // heading contains all allowed chars in fragment (hash) in accordance with RFC 3986
+            html(dedent`
+                ## «Heading» “with” "quotes'
+
+                Content
+                `),
+        ).toMatchSnapshot();
+    });
+
     describe('with extract title', () => {
         const transformWithTitle = (text: string) => {
             const {