Introduction

AsyncStorage dependency is fixed, hurray!

This is a i18next cache layer to be used in the browser. It will load and cache resources from AsyncStorage and can be used in combination with the chained backend.

Getting started

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

npx expo install i18next-async-storage-backend2 @react-native-async-storage/async-storage
# or
npm install i18next-async-storage-backend2

Wiring up with the chained backend:

import i18next from 'i18next';
import Backend from 'i18next-chained-backend';
import AsyncStorageBackend from 'i18next-async-storage-backend2'; // primary use cache
import XHR from 'i18next-xhr-backend'; // fallback xhr load

i18next.use(Backend).init({
  backend: {
    backends: [
      AsyncStorageBackend, // primary
      XHR // fallback
    ],
    backendOptions: [
      {
        /* below options */
      },
      {
        loadPath: '/locales/{{lng}}/{{ns}}.json' // xhr load path for my own fallback
      }
    ]
  }
});

Cache Backend Options

{
  // prefix for stored languages
  prefix: 'i18next_res_',

  // expiration
  expirationTime: 7*24*60*60*1000,

  // language versions
  versions: {},

  // namespaces to skip the caching
  skipCache: []
};

• Contrary to cookies behavior, the cache will respect updates to expirationTime. If you set 7 days and later update to 10 days, the cache will persist for 10 days

• Passing in a versions object (ex.: versions: { en: 'v1.2', fr: 'v1.1' }) will give you control over the cache based on translations version. This setting works along expirationTime, so a cached translation will still expire even though the version did not change. You can still set expirationTime far into the future to avoid this

• Passing an array like skipCache: ['namespace1', 'namespace2'], the namespaces on that array will never be cached or recovered from cache

Wiring up a service backend with the chained backend:

import i18next from 'i18next';
import Backend from 'i18next-chained-backend';
import AsyncStorageBackend from 'i18next-async-storage-backend2'; // primary use cache
import ServiceBackend from 'i18next-service-backend'; // fallback service backend

const TRANSLATION_BACKEND = 'https://api.spacetranslate.com';
const TRANSLATION_BACKEND_PROJECTID = '[projectId]'; // i.e. [projectId].spacetranslate.com

i18next.use(Backend).init({
  backend: {
    backends: [
      AsyncStorageBackend, // primary
      ServiceBackend // fallback
    ],
    backendOptions: [
      {
        // prefix for stored languages
        prefix: 'i18next_res_',

        // expiration
        expirationTime: 7 * 24 * 60 * 60 * 1000,

        // language versions
        versions: {}

        // namespaces to be excluded from the cache
        skipCache: ['namespace-that-i-dont-want-to-cache']
      },
      {
        service: TRANSLATION_BACKEND,
        projectId: TRANSLATION_BACKEND_PROJECTID,
        referenceLng: 'en',
        version: 'latest'
      }
    ]
  }
});