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expo-localization

Open Beta Documentation Amazon offers this technical documentation as part of a pre-release, open beta. The features described might change as Amazon receives feedback and iterates on the features. For the most current feature information, see the latest Release Notes.

@amazon-devices/expo-localization provides an interface for native user localization information.

This library provides the getCalendars() and getLocales() method and their corresponding hooks, which return specific information about a user's locale settings, for example languageCode, uses24HourClock, currencyCode, and textDirection. The library doesn't provide any methods for formatting text or values. Hooks trigger a re-render when the app locale changes.

This library is system-deployed and available to React Native for Vega apps without a separate installation process. This autolinking library connects to your app at runtime. Compatibility is guaranteed only between the library and the version of React Native for Vega for which it is built.

Installation
Examples
API reference
- Constants
- Hooks
- Methods
Known issues and limitations
Supported versions
Related topics

Installation

Add the JavaScript library dependency in the package.json file.

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 "dependencies": {
 ...
 "@amazon-devices/expo-localization": "~2.0.1",
 "@amazon-devices/keplerscript-turbomodule-api": "~1.0.0",
 ...
 }

Reinstall dependencies using the npm install command.

Examples

The example below demonstrates how to retrieve a user's language code.

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import React from 'react';
import {StyleSheet, Text, View} from 'react-native';
import {useLocales, useCalendars} from '@amazon-devices/expo-localization';

export const App = () => {
  const locales = useLocales();
  const calendars = useCalendars();

  return (
    <View style={styles.container}>
      <Text style={styles.text}>useLocales():</Text>
      <Text style={styles.text}>{JSON.stringify(locales, null, 2)}</Text>
      <Text style={styles.text}>useCalendars():</Text>
      <Text style={styles.text}>{JSON.stringify(calendars, null, 2)}</Text>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: 'row',
    backgroundColor: 'white',
  },
  text: {
    color: 'black',
    fontSize: 32,
  },
});

API reference

See the documentation page for information about this library and API reference: Official Expo documentation for expo-localization.

Constants

Constant	Description
`locale`	An IETF BCP 47 language tag, consisting of a two-character language code and optional script, region, and variant codes. Consider using `Localization.getLocales()` for a list of user preferred locales instead.

Hooks

Hook Description

useCalendars Lists a user's preferred calendars and returns an array of objects of type Calendar. Guaranteed to contain at least one element. Always returns a single element, but it's likely to return a user preference list on some platforms in the future. If the OS settings change, the hook rerenders with a new list of calendars.

useLocales Lists a user's locales and returns as an array of objects of type Locale. Guaranteed to contain at least one element. These are returned in the order the user defines in their device settings. On the web, currency and measurement systems aren't provided, instead they're returned as null. If needed, you can infer currencies and measurements from the current region using a lookup table. If the OS settings change, the hook rerenders with a new list of locales.

Hook	Description
`useCalendars`	Lists a user's preferred calendars and returns an array of objects of type `Calendar`. Guaranteed to contain at least one element. Always returns a single element, but it's likely to return a user preference list on some platforms in the future. If the OS settings change, the hook rerenders with a new list of calendars.
`useLocales`	Lists a user's locales and returns as an array of objects of type `Locale`. Guaranteed to contain at least one element. These are returned in the order the user defines in their device settings. On the web, currency and measurement systems aren't provided, instead they're returned as null. If needed, you can infer currencies and measurements from the current region using a lookup table. If the OS settings change, the hook rerenders with a new list of locales.

Methods

Method	Description	Supported
`getCalendars`	Lists a user's preferred calendars and returns an array of objects of type `Calendar`. Guaranteed to contain at least one element. Always returns a single element, but it's likely to return a user preference list on some platforms in the future.	✅ Yes
`getLocales`	Lists a user's locales, returned as an array of objects of type `Locale`. Guaranteed to contain at least one element. These are returned in the order the user defines in their device settings. On the web, currency and measurement systems aren't provided, instead they're returned as null. If needed, you can infer currencies and measurements from the current region using a lookup table.	✅ Yes
`getLocalizationAsync`	Deprecated.	❌ No

Known issues and limitations

The region field on Localization type is always null on Vega.
Functions useLocales(), useCalendars(), getCalendars(), and getLocales() always return an array with one item in it, while other platforms might return an empty array or multiple valid locales/calendars.

Supported versions

Package Version	Based On	@amazon-devices/react-native-kepler version
2.0.x	14.6.0	2.0.x

Supported Third-Party Libraries and Services.

Last updated: Sep 30, 2025