Revert "[docs] Fix heading fragment id mismatch"

This reverts commit 0762f98.

Author: eps1lon

docs/src/modules/components/MarkdownElement.js

@@ -19,6 +19,26 @@ marked.Lexer.prototype.lex = function lex(src) {
 };
 
 const renderer = new marked.Renderer();
+renderer.heading = (text, level) => {
+  // Small title. No need for an anchor.
+  // It's reducing the risk of duplicated id and it's fewer elements in the DOM.
+  if (level >= 4) {
+    return `<h${level}>${text}</h${level}>`;
+  }
+
+  // eslint-disable-next-line no-underscore-dangle
+  const hash = textToHash(text, global.__MARKED_UNIQUE__);
+
+  return [
+    `<h${level}>`,
+    `<a class="anchor-link" id="${hash}"></a>`,
+    text,
+    `<a class="anchor-link-style" aria-hidden="true" aria-label="anchor" href="#${hash}">`,
+    '<svg><use xlink:href="#anchor-link-icon" /></svg>',
+    '</a>',
+    `</h${level}>`,
+  ].join('');
+};
 
 const externs = [
   'https://material.io/',
@@ -284,28 +304,6 @@ function MarkdownElement(props) {
   // eslint-disable-next-line no-underscore-dangle
   global.__MARKED_USER_LANGUAGE__ = userLanguage;
 
-  // need to reset on every render to make textToHash concurrent-safe
-  const headingIdCache = {};
-  renderer.heading = (headingText, level) => {
-    // Small title. No need for an anchor.
-    // It's reducing the risk of duplicated id and it's fewer elements in the DOM.
-    if (level >= 4) {
-      return `<h${level}>${headingText}</h${level}>`;
-    }
-
-    const hash = textToHash(headingText, headingIdCache);
-
-    return [
-      `<h${level}>`,
-      `<a class="anchor-link" id="${hash}"></a>`,
-      headingText,
-      `<a class="anchor-link-style" aria-hidden="true" aria-label="anchor" href="#${hash}">`,
-      '<svg><use xlink:href="#anchor-link-icon" /></svg>',
-      '</a>',
-      `</h${level}>`,
-    ].join('');
-  };
-
   /* eslint-disable react/no-danger */
   return (
     <div

docs/src/modules/components/useMarkdownDocs.js

@@ -86,6 +86,9 @@ ${headers.components
   `);
   }
 
+  // eslint-disable-next-line no-underscore-dangle
+  global.__MARKED_UNIQUE__ = {};
+
   const element = (
     <React.Fragment>
       <svg style={{ display: 'none' }} xmlns="http://www.w3.org/2000/svg">

docs/src/modules/utils/textToHash.js

@@ -9,12 +9,6 @@ function makeUnique(hash, unique, i = 1) {
   return makeUnique(hash, unique, i + 1);
 }
 
-/**
- * @param {string} text
- * @param {object} unique - cache object, if provided textToHash has side-effects.
- *                          If you use it when rendering a react component be sure
- *                          to always pass a new cache object.
- */
 export default function textToHash(text, unique = {}) {
   return makeUnique(
     encodeURI(