Heading: Auto-generated anchors hide implementation details

packages/block-library/src/heading/autogenerate-anchors.js

@@ -3,6 +3,13 @@
  */
 import { deburr, trim } from 'lodash';
 
+/**
+ * Object map tracking anchors.
+ *
+ * @type {Record<string, string | null>}
+ */
+const anchors = {};
+
 /**
  * Returns the text without markup.
  *
@@ -36,30 +43,39 @@ const getSlug = ( content ) => {
 /**
  * Generate the anchor for a heading.
  *
- * @param {string}   clientId          The block ID.
- * @param {string}   content           The block content.
- * @param {string[]} allHeadingAnchors An array containing all headings anchors.
+ * @param {string} clientId The block ID.
+ * @param {string} content  The block content.
  *
  * @return {string|null} Return the heading anchor.
  */
-export const generateAnchor = ( clientId, content, allHeadingAnchors ) => {
+export const generateAnchor = ( clientId, content ) => {
 	const slug = getSlug( content );
 	// If slug is empty, then return null.
 	// Returning null instead of an empty string allows us to check again when the content changes.
 	if ( '' === slug ) {
 		return null;
 	}
 
-	delete allHeadingAnchors[ clientId ];
+	delete anchors[ clientId ];
 
 	let anchor = slug;
 	let i = 0;
 
 	// If the anchor already exists in another heading, append -i.
-	while ( Object.values( allHeadingAnchors ).includes( anchor ) ) {
+	while ( Object.values( anchors ).includes( anchor ) ) {
 		i += 1;
 		anchor = slug + '-' + i;
 	}
 
 	return anchor;
 };
+
+/**
+ * Set the anchor for a heading.
+ *
+ * @param {string}      clientId The block ID.
+ * @param {string|null} anchor   The block anchor.
+ */
+export const setAnchor = ( clientId, anchor ) => {
+	anchors[ clientId ] = anchor;
+};

packages/block-library/src/heading/edit.js

@@ -22,9 +22,7 @@ import {
  * Internal dependencies
  */
 import HeadingLevelDropdown from './heading-level-dropdown';
-import { generateAnchor } from './autogenerate-anchors';
-
-const allHeadingAnchors = {};
+import { generateAnchor, setAnchor } from './autogenerate-anchors';
 
 function HeadingEdit( {
 	attributes,
@@ -54,28 +52,23 @@ function HeadingEdit( {
 			// This side-effect should not create an undo level.
 			__unstableMarkNextChangeAsNotPersistent();
 			setAttributes( {
-				anchor: generateAnchor( clientId, content, allHeadingAnchors ),
+				anchor: generateAnchor( clientId, content ),
 			} );
 		}
+		setAnchor( clientId, anchor );
 
-		allHeadingAnchors[ clientId ] = anchor;
-		return () => {
-			delete allHeadingAnchors[ clientId ];
-		};
+		// Remove anchor map when block unmounts.
+		return () => setAnchor( clientId, null );
 	}, [ content, anchor ] );
 
 	const onContentChange = ( value ) => {
 		const newAttrs = { content: value };
 		if (
 			! anchor ||
 			! value ||
-			generateAnchor( clientId, content, allHeadingAnchors ) === anchor
+			generateAnchor( clientId, content ) === anchor
 		) {
-			newAttrs.anchor = generateAnchor(
-				clientId,
-				value,
-				allHeadingAnchors
-			);
+			newAttrs.anchor = generateAnchor( clientId, value );
 		}
 		setAttributes( newAttrs );
 	};