verify country code we get from geo

src/components/InternationalPhoneCodeSelect.tsx

@@ -3,14 +3,15 @@ import {Image} from 'expo-image'
 import {msg} from '@lingui/macro'
 import {useLingui} from '@lingui/react'
 
-import {getCountriesWithTelephoneCodes} from '#/lib/international-telephone-codes'
+import {
+  getCountriesWithTelephoneCodes,
+  getDefaultCountry,
+} from '#/lib/international-telephone-codes'
 import {isWeb} from '#/platform/detection'
 import {useGeolocationStatus} from '#/state/geolocation'
 import {atoms as a, web} from '#/alf'
 import * as Select from '#/components/Select'
 
-export const DEFAULT_PHONE_COUNTRY = 'US'
-
 /**
  * Country picker for a phone number input
  *
@@ -27,7 +28,9 @@ export function InternationalPhoneCodeSelect({
   const {_, i18n} = useLingui()
   const {location} = useGeolocationStatus()
 
-  const defaultCountry = location?.countryCode || DEFAULT_PHONE_COUNTRY
+  const defaultCountry = useMemo(() => {
+    return getDefaultCountry(location)
+  }, [location])
 
   const items = useMemo(() => {
     const telCountryMap = getCountriesWithTelephoneCodes(i18n)

src/lib/international-telephone-codes.ts

@@ -1,4 +1,4 @@
-import {type I18n} from '@lingui/core'
+import {type I18n, i18n} from '@lingui/core'
 import {msg} from '@lingui/macro'
 
 export function getCountriesWithTelephoneCodes(i18n: I18n) {
@@ -1505,3 +1505,17 @@ export function getCountriesWithTelephoneCodes(i18n: I18n) {
     },
   }
 }
+
+const DEFAULT_PHONE_COUNTRY = 'US'
+
+export function getDefaultCountry(location?: {countryCode?: string}) {
+  const supportedCountries = Object.keys(getCountriesWithTelephoneCodes(i18n)) // ok to use default i18n here because we don't use the name
+
+  if (
+    location?.countryCode &&
+    supportedCountries.includes(location.countryCode.toUpperCase())
+  ) {
+    return location.countryCode.toUpperCase()
+  }
+  return DEFAULT_PHONE_COUNTRY
+}