From 8b07525c3d5e12b2c26fd3557eebdada9500e32e Mon Sep 17 00:00:00 2001
From: Ella <4710635+ellatrix@users.noreply.github.com>
Date: Tue, 18 Jun 2024 04:54:04 +0200
Subject: [PATCH] Performance: run block variation hook only for matches
 (#62617)

Co-authored-by: ellatrix <ellatrix@git.wordpress.org>
Co-authored-by: aaronrobertshaw <aaronrobertshaw@git.wordpress.org>
---
 .../src/hooks/block-style-variation.js        | 25 ++++++++++++++++---
 packages/block-editor/src/hooks/utils.js      |  4 ++-
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/packages/block-editor/src/hooks/block-style-variation.js b/packages/block-editor/src/hooks/block-style-variation.js
index ee02b97d216704..964f0d19bb8616 100644
--- a/packages/block-editor/src/hooks/block-style-variation.js
+++ b/packages/block-editor/src/hooks/block-style-variation.js
@@ -17,6 +17,23 @@ import { useStyleOverride } from './utils';
 import { store as blockEditorStore } from '../store';
 import { globalStylesDataKey } from '../store/private-keys';
 
+const VARIATION_PREFIX = 'is-style-';
+
+function getVariationMatches( className ) {
+	if ( ! className ) {
+		return [];
+	}
+	return className.split( /\s+/ ).reduce( ( matches, name ) => {
+		if ( name.startsWith( VARIATION_PREFIX ) ) {
+			const match = name.slice( VARIATION_PREFIX.length );
+			if ( match !== 'default' ) {
+				matches.push( match );
+			}
+		}
+		return matches;
+	}, [] );
+}
+
 /**
  * Get the first block style variation that has been registered from the class string.
  *
@@ -28,14 +45,13 @@ import { globalStylesDataKey } from '../store/private-keys';
 function getVariationNameFromClass( className, registeredStyles = [] ) {
 	// The global flag affects how capturing groups work in JS. So the regex
 	// below will only return full CSS classes not just the variation name.
-	const matches = className?.match( /\bis-style-(?!default)(\S+)\b/g );
+	const matches = getVariationMatches( className );
 
 	if ( ! matches ) {
 		return null;
 	}
 
-	for ( const variationClass of matches ) {
-		const variation = variationClass.substring( 9 ); // Remove 'is-style-' prefix.
+	for ( const variation of matches ) {
 		if ( registeredStyles.some( ( style ) => style.name === variation ) ) {
 			return variation;
 		}
@@ -94,7 +110,7 @@ function useBlockProps( { name, className, clientId } ) {
 
 	const registeredStyles = getBlockStyles( name );
 	const variation = getVariationNameFromClass( className, registeredStyles );
-	const variationClass = `is-style-${ variation }-${ clientId }`;
+	const variationClass = `${ VARIATION_PREFIX }${ variation }-${ clientId }`;
 
 	const { settings, styles } = useBlockSyleVariation(
 		name,
@@ -152,5 +168,6 @@ function useBlockProps( { name, className, clientId } ) {
 export default {
 	hasSupport: () => true,
 	attributeKeys: [ 'className' ],
+	isMatch: ( { className } ) => getVariationMatches( className ).length > 0,
 	useBlockProps,
 };
diff --git a/packages/block-editor/src/hooks/utils.js b/packages/block-editor/src/hooks/utils.js
index 4338262300c618..d4eb7df553d3c0 100644
--- a/packages/block-editor/src/hooks/utils.js
+++ b/packages/block-editor/src/hooks/utils.js
@@ -582,6 +582,7 @@ export function createBlockListBlockFilter( features ) {
 						hasSupport,
 						attributeKeys = [],
 						useBlockProps,
+						isMatch,
 					} = feature;
 
 					const neededProps = {};
@@ -595,7 +596,8 @@ export function createBlockListBlockFilter( features ) {
 						// Skip rendering if none of the needed attributes are
 						// set.
 						! Object.keys( neededProps ).length ||
-						! hasSupport( props.name )
+						! hasSupport( props.name ) ||
+						( isMatch && ! isMatch( neededProps ) )
 					) {
 						return null;
 					}