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


When using this module, only the ICU message format is respected, this means the i18next format interpolation will not work. So for example instead of Hy {{name}}! it is Hy {name}!

Getting started

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

# npm package
$ npm install i18next-icu
# peer dependencies
$ npm install intl-messageformat

Wiring up:

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

  • 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

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,

  // 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: '',

  // Will be run when parser throws an error. Can return any string, which can be used as a fallback, in case of broken translation.
  // If omitted, the default swallows the error and returns the unsubstituted string (res)
  parseErrorHandler: (err, key, res, options) => {},

  // Transform the language code prior to ICU locale parsing, useful for supporting psuedo-locales like en-ZZ
  // If omitted, the default leaves the language code as is
  parseLngForICU: (lng) => lng,

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

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

  i18nFormat: options

more complete sample

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

  lng: "en",
  resources: {
    en: {
      translation: {
          "You have {numPhotos, plural, " +
          "=0 {no photos.}" +
          "=1 {one photo.}" +
          "other {# photos.}}"

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


Using i18next-icu - non of the i18next specific stuff will be available. You will have to rely on what intl-messageformat provides by calling the t function with needed options.

All extra features build around i18next plurals, interpolation, context do not get applied to messageformat based keys.

Migration guide

1.x.x -> 2.0.0

  • updated intl-messageformat dependency. Adding locales-data is no longer needed.

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