Introduction

This changes i18n format from i18next json to ICU using yahoo/intl-messageformat

Getting started

Source can be loaded via npm or downloaded from this repo.

# npm package
$ npm install i18next-icu

Wiring up:

import i18next from "i18next";
import ICU from "i18next-icu";

i18next.use(ICU).init(i18nextOptions);

• As with all modules you can either pass the constructor function (class) to the i18next.use or a concrete instance.
• If you don't use a module loader it will be added to window.i18nextICU

Plural Support

• While on node.js all plurals will work out of the box in browser you will need to load additional locale data files like:

import i18next from 'i18next';
import ICU from 'i18next-icu';

import fr from 'i18next-icu/locale-data/fr';

i18next
  .use(ICU)
  .init({
    i18nFormat: {
      localeData: fr // you also can pass in array of localeData
      formats: {
        // https://github.com/yahoo/intl-messageformat#user-defined-formats
      }
    }
  });

// or for react-i18next when using SSR
import i18next from 'i18next';
import ICU from 'i18next-icu';
import fr from 'i18next-icu/locale-data/fr';

const icu = new ICU();
icu.addLocaleData(fr);
icu.addUserDefinedFormats({ /* https://github.com/yahoo/intl-messageformat#user-defined-formats */ })

i18next
  .use(icu)
  .init({
    i18nFormat: {}
  });

Backend Options

{
  // per default icu functions are parsed once and cached for subsequent calls
  memoize: true,

  // memoize if not having a lookup and just using the key fallback as value
  memoizeFallback: false,

  // array or single object of loaded 'i18next-icu/locale-data
  localeData: null,

  // which events should clear the cache, can be set to false or string of events separated by " "
  bindI18n: '',

  // which events on resourceSource should clear the cache, can be set to false or string of events separated by " "
  bindI18nStore: ''
}

Options can be passed in by setting options.i18nFormat in i18next.init:

import i18next from "i18next";
import ICU from "i18next-icu";

i18next.use(ICU).init({
  i18nFormat: options
});

more complete sample

import i18next from "i18next";
import ICU from "i18next-icu";

i18next.use(ICU).init({
  lng: "en",
  resources: {
    en: {
      translation: {
        key:
          "You have {numPhotos, plural, " +
          "=0 {no photos.}" +
          "=1 {one photo.}" +
          "other {# photos.}}"
      }
    }
  }
});

i18next.t("key", { numPhotos: 1000 }); // -> You have 1,000 photos.