From d4b406de048590056d1afeef4ec83af291fb597e Mon Sep 17 00:00:00 2001
From: Danny Gleckler <daniel.gleckler@d2l.com>
Date: Mon, 10 Mar 2025 16:26:17 -0400
Subject: [PATCH 1/2] Filter out bad locales

---
 lib/common.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/common.js b/lib/common.js
index 5bdcb73..a8e492e 100644
--- a/lib/common.js
+++ b/lib/common.js
@@ -93,7 +93,7 @@ class DocumentLocaleSettings {
 
 	constructor() {
 		this._cache = new Map();
-		this._htmlElem = window.document.getElementsByTagName('html')[0];
+		this._htmlElem = document.documentElement;
 		this._listeners = [];
 		this._overrides = {};
 		this._observer = new MutationObserver(this._handleObserverChange.bind(this));
@@ -227,8 +227,11 @@ export function getDocumentLocaleSettings() {
 	return documentLocaleSettings;
 }
 
+const localeRegEx = /[^a-zA-Z0-9-]/g;
+
 function updateLocalNames() {
-	const localName = new Intl.DisplayNames(documentLocaleSettings.language || navigator.language, { type: 'language' });
+	const possibleLocales = [documentLocaleSettings.language, navigator.language, defaultLocale].filter(l => l && !localeRegEx.test(l));
+	const localName = new Intl.DisplayNames(possibleLocales, { type: 'language' });
 	supportedLocalesDetails.forEach(l => {
 		l.localName = localName.of(l.overrideCode || l.code);
 	});

From f5566463a2fa13705f764ef04044196b218d2743 Mon Sep 17 00:00:00 2001
From: Danny Gleckler <daniel.gleckler@d2l.com>
Date: Mon, 10 Mar 2025 16:37:56 -0400
Subject: [PATCH 2/2] Fail gracefully

---
 lib/common.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/common.js b/lib/common.js
index a8e492e..978cde9 100644
--- a/lib/common.js
+++ b/lib/common.js
@@ -231,7 +231,12 @@ const localeRegEx = /[^a-zA-Z0-9-]/g;
 
 function updateLocalNames() {
 	const possibleLocales = [documentLocaleSettings.language, navigator.language, defaultLocale].filter(l => l && !localeRegEx.test(l));
-	const localName = new Intl.DisplayNames(possibleLocales, { type: 'language' });
+	let localName;
+	try {
+		localName = new Intl.DisplayNames(possibleLocales, { type: 'language' });
+	} catch {
+		return;
+	}
 	supportedLocalesDetails.forEach(l => {
 		l.localName = localName.of(l.overrideCode || l.code);
 	});