From 5fa160746c9aee6427f3e6fd0129ab1805813d06 Mon Sep 17 00:00:00 2001
From: Grant Kinney <hi@grant.mk>
Date: Sun, 17 Mar 2024 16:35:26 -0500
Subject: [PATCH] Font Library: fix JS errors when activating or deactivating
 system fonts

---
 .../components/global-styles/font-library-modal/context.js  | 6 +++---
 .../global-styles/font-library-modal/utils/index.js         | 6 +++---
 .../font-library-modal/utils/preview-styles.js              | 4 ++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/packages/edit-site/src/components/global-styles/font-library-modal/context.js b/packages/edit-site/src/components/global-styles/font-library-modal/context.js
index 2c04a72bb6c6e..4a1f34a095699 100644
--- a/packages/edit-site/src/components/global-styles/font-library-modal/context.js
+++ b/packages/edit-site/src/components/global-styles/font-library-modal/context.js
@@ -425,15 +425,15 @@ function FontLibraryProvider( { children } ) {
 
 		const isFaceActivated = isFontActivated(
 			font.slug,
-			face.fontStyle,
-			face.fontWeight,
+			face?.fontStyle,
+			face?.fontWeight,
 			font.source
 		);
 
 		if ( isFaceActivated ) {
 			loadFontFaceInBrowser(
 				face,
-				getDisplaySrcFromFontFace( face.src ),
+				getDisplaySrcFromFontFace( face?.src ),
 				'all'
 			);
 		} else {
diff --git a/packages/edit-site/src/components/global-styles/font-library-modal/utils/index.js b/packages/edit-site/src/components/global-styles/font-library-modal/utils/index.js
index 07153bcd1b9c3..b3deb8fcec499 100644
--- a/packages/edit-site/src/components/global-styles/font-library-modal/utils/index.js
+++ b/packages/edit-site/src/components/global-styles/font-library-modal/utils/index.js
@@ -134,9 +134,9 @@ export function unloadFontFaceInBrowser( fontFace, removeFrom = 'all' ) {
 	const unloadFontFace = ( fonts ) => {
 		fonts.forEach( ( f ) => {
 			if (
-				f.family === formatFontFaceName( fontFace.fontFamily ) &&
-				f.weight === fontFace.fontWeight &&
-				f.style === fontFace.fontStyle
+				f.family === formatFontFaceName( fontFace?.fontFamily ) &&
+				f.weight === fontFace?.fontWeight &&
+				f.style === fontFace?.fontStyle
 			) {
 				fonts.delete( f );
 			}
diff --git a/packages/edit-site/src/components/global-styles/font-library-modal/utils/preview-styles.js b/packages/edit-site/src/components/global-styles/font-library-modal/utils/preview-styles.js
index ef2b04feceb5e..d0b5d1389d801 100644
--- a/packages/edit-site/src/components/global-styles/font-library-modal/utils/preview-styles.js
+++ b/packages/edit-site/src/components/global-styles/font-library-modal/utils/preview-styles.js
@@ -87,6 +87,10 @@ export function formatFontFamily( input ) {
  * formatFontFaceName(", 'Open Sans', 'Helvetica Neue', sans-serif") => "Open Sans"
  */
 export function formatFontFaceName( input ) {
+	if ( ! input ) {
+		return '';
+	}
+
 	let output = input.trim();
 	if ( output.includes( ',' ) ) {
 		output = output