Internationalization utilities for client-side localization.

https://codex.wordpress.org/I18n_for_WordPress_Developers

Install the module:

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 ES2015+ such as lower versions of IE then using core-js or @babel/polyfill will add support for these methods. Learn more about it in Babel docs.

import { sprintf, _n } from '@wordpress/i18n';

sprintf( _n( '%d hat', '%d hats', 4, 'text-domain' ), 4 );
// 4 hats

Note that you will not need to specify domain for the strings.

You can use the WordPress i18n babel plugin to generate a .pot file containing all your localized strings.

The package also includes a pot-to-php script used to generate a php files containing the messages listed in a .pot file. This is useful to trick WordPress.org translation strings discovery since at the moment, WordPress.org is not capable of parsing strings directly from JavaScript files.

npx pot-to-php languages/myplugin.pot languages/myplugin-translations.php text-domain

__( text: string, domain: string ): string

Retrieve the translation of text.

See: https://developer.wordpress.org/reference/functions/__/

_x( text: string, context: string, domain: string ): string

Retrieve translated string with gettext context.

See: https://developer.wordpress.org/reference/functions/_x/

_n( single: string, plural: string, number: Number, domain: string ): string

Translates and retrieves the singular or plural form based on the supplied number.

See: https://developer.wordpress.org/reference/functions/_n/

_nx( single: string, plural: string, number: Number, context: string, domain: string ): string

Translates and retrieves the singular or plural form based on the supplied number, with gettext context.

See: https://developer.wordpress.org/reference/functions/_nx/

sprintf( format: string, ...args: mixed[] ): string

Returns a formatted string.

See: http:https://www.diveintojavascript.com/projects/javascript-sprintf

setLocaleData( data: Object, domain: string )

Creates a new Jed instance with specified locale data configuration.