Protect util handling, update test

src/locale/helpers.ts

@@ -188,9 +188,10 @@ export function fixLegacyLanguageCode(code: string | null): string | null {
  *
  * If no match, returns `en`.
  */
-export function findSupportedAppLanguage(languageTags: string[]) {
+export function findSupportedAppLanguage(languageTags: (string | undefined)[]) {
   const supported = new Set(Object.values(AppLanguage))
   for (const tag of languageTags) {
+    if (!tag) continue
     if (supported.has(tag as AppLanguage)) {
       return tag
     }

src/state/persisted/schema.ts

@@ -146,7 +146,7 @@ export const defaults: Schema = {
       .slice(0, 6),
     // try full language tag first, then fallback to language code
     appLanguage: findSupportedAppLanguage([
-      deviceLocales[0].languageTag,
+      deviceLocales.at(0)?.languageTag,
       deviceLanguageCodes[0],
     ]),
   },

src/state/session/__tests__/session-test.ts

@@ -10,6 +10,10 @@ jest.mock('jwt-decode', () => ({
   },
 }))
 
+jest.mock('expo-localization', () => ({
+  getLocales: () => [],
+}))
+
 describe('session', () => {
   it('can log in and out', () => {
     let state = getInitialState([])