# Internationalization (i18n)
Internationalization utilities for client-side localization. See [How to Internationalize Your Plugin](https://developer.wordpress.org/plugins/internationalization/how-to-internationalize-your-plugin/) for server-side documentation.
## Installation
Install the module:
```bash
npm install @wordpress/i18n --save
```
_This package assumes that your code will run in an **ES2015+** environment. If you're using an environment that has limited or no support for such language features and APIs, you should include [the polyfill shipped in `@wordpress/babel-preset-default`](https://github.com/WordPress/gutenberg/tree/HEAD/packages/babel-preset-default#polyfill) in your code._
## Usage
```js
import { sprintf, _n } from '@wordpress/i18n';
sprintf( _n( '%d hat', '%d hats', 4, 'text-domain' ), 4 );
// 4 hats
```
For a complete example, see the [Internationalization section of the Block Editor Handbook](https://developer.wordpress.org/block-editor/developers/internationalization/).
## API
### createI18n
Create an i18n instance
_Parameters_
- _initialData_ `[LocaleData< TextDomain >]`: Locale data configuration.
- _initialDomain_ `[TextDomain]`: Domain for which configuration applies.
- _hooks_ `[Hooks]`: Hooks implementation.
_Returns_
- `I18n< TextDomain >`: I18n instance.
### defaultI18n
Default, singleton instance of `I18n`.
### getLocaleData
Returns locale data by domain in a Jed-formatted JSON object shape.
_Related_
-
_Parameters_
- _domain_ `[ string | undefined ]`: Domain for which to get the data.
_Returns_
- `LocaleData`: Locale data.
### hasTranslation
Check if there is a translation for a given string (in singular form).
_Parameters_
- _single_ `string`: Singular form of the string to look up.
- _context_ `string`: Context information for the translators.
- _domain_ `string`: Domain to retrieve the translated text.
_Returns_
- `boolean`: Whether the translation exists or not.
### isRTL
Check if current locale is RTL.
**RTL (Right To Left)** is a locale property indicating that text is written from right to left. For example, the `he` locale (for Hebrew) specifies right-to-left. Arabic (ar) is another common language written RTL. The opposite of RTL, LTR (Left To Right) is used in other languages, including English (`en`, `en-US`, `en-GB`, etc.), Spanish (`es`), and French (`fr`).
_Returns_
- `boolean`: Whether locale is RTL.
### resetLocaleData
Resets all current Tannin instance locale data and sets the specified locale data for the domain. Accepts data in a Jed-formatted JSON object shape.
_Related_
-
_Parameters_
- _data_ `[LocaleData]`: Locale data configuration.
- _domain_ `[string | undefined]`: Domain for which configuration applies.
### setLocaleData
Merges locale data into the Tannin instance by domain. Accepts data in a Jed-formatted JSON object shape.
_Related_
-
_Parameters_
- _data_ `[LocaleData ]`: Locale data configuration.
- _domain_ `[string | undefined]`: Domain for which configuration applies.
### sprintf
Returns a formatted string.
_Related_
-
_Parameters_
- _format_ `T | TransformedText< T >`: The format of the string to generate.
- _args_ `DistributeSprintfArgs< T >`: Arguments to apply to the format.
_Returns_
- `TransformedText< T >`: The formatted string.
### subscribe
Subscribes to changes of locale data
_Parameters_
- _callback_ `SubscribeCallback`: Subscription callback
_Returns_
- `UnsubscribeCallback`: Unsubscribe callback
### \_n
Translates and retrieves the singular or plural form based on the supplied number.
_Related_
-
_Parameters_
- _single_ `Single`: The text to be used if the number is singular.
- _plural_ `Plural`: The text to be used if the number is plural.
- _number_ `number`: The number to compare against to use either the singular or plural form.
- _domain_ `string | undefined`: Domain to retrieve the translated text.
_Returns_
- `TransformedText`: The translated singular or plural form.
### \_nx
Translates and retrieves the singular or plural form based on the supplied number, with gettext context.
_Related_
-
_Parameters_
- _single_ `Single`: The text to be used if the number is singular.
- _single_ `Single`: The text to be used if the number is singular.
- _plural_ `Plural`: The text to be used if the number is plural.
- _number_ `number`: The number to compare against to use either the singular or plural form.
- _context_ `string`: Context information for the translators.
- _domain_ `[string | undefined]`: Domain to retrieve the translated text.
_Returns_
- `TransformedText`: The translated singular or plural form.
### \_x
Retrieve translated string with gettext context.
_Related_
-
_Parameters_
- _text_ `Text`: Text to translate.
- _context_ `string`: Context information for the translators.
- _domain_ `string | undefined`: Domain to retrieve the translated text.
_Returns_
- `TransformedText`: Translated context string without pipe.
### \_\_
Retrieve the translation of text.
_Related_
-
_Parameters_
- _text_ `Text`: Text to translate.
- _domain_ `string | undefined`: Domain to retrieve the translated text.
_Returns_
- `TransformedText`: Translated text.
## Contributing to this package
This is an individual package that's part of the Gutenberg project. The project is organized as a monorepo. It's made up of multiple self-contained software packages, each with a specific purpose. The packages in this monorepo are published to [npm](https://www.npmjs.com/) and used by [WordPress](https://make.wordpress.org/core/) as well as other software projects.
To find out more about contributing to this package or Gutenberg as a whole, please read the project's main [contributor guide](https://github.com/WordPress/gutenberg/tree/HEAD/CONTRIBUTING.md).
