Introduction

This is a i18next backend to be used with node.js for the locize service. It's for the node.js server what the i18next-locize-backend is for the browser.

Getting started

Source can be loaded via npm.

$ npm install i18next-node-locize-backend

Wiring up:

var i18next = require('i18next');
var Backend = require('i18next-node-locize-backend');

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

As with all modules you can either pass the constructor function (class) to the i18next.use or a concrete instance.

Backend Options

{
  // the id of your locize project
  projectId: '[PROJECTID]',

  // add an api key if you want to send missing keys
  apiKey: '[APIKEY]',

  // the reference language of your project
  referenceLng: '[LNG]',

  // version - defaults to latest
  version: '[VERSION]',

  // private - set to true if you version on locize is set to use private publish
  private: false
}

Options can be passed in:

preferred - by setting options.backend in i18next.init:

var i18next = require('i18next');
var Backend = require('i18next-node-locize-backend');

i18next
  .use(Backend)
  .init({
    backend: options
  });

on construction:

var Backend = require('i18next-node-locize-backend');
var backend = new Backend(options);

by calling init:

var Backend = require('i18next-node-locize-backend');
var backend = new Backend();
backend.init(options);

Additional API endpoints

backend.getLanguages

Will return a list of all languages in your project including percentage of translations done per version.

import Backend from 'i18next-node-locize-backend';
const backend = new Backend(options);

backend.getLanguages((err, data) => {
  /*
  data is:

  {
    "en": {
      "name": "English",
      "nativeName": "English",
      "isReferenceLanguage": true,
      "translated": {
        "latest": 1
      }
    },
    "de": {
      "name": "German",
      "nativeName": "Deutsch",
      "isReferenceLanguage": false,
      "translated": {
        "latest": 0.9
      }
    }
  }
  */
});

// or
i18next.services.backendConnector.backend.getLanguages(callback);

backend.getOptions

Will return an object containing useful informations for the i18next init options.

import Backend from 'i18next-node-locize-backend';
const backend = new Backend(options);

backend.getOptions((err, data) => {
  /*
  data is:

  {
    fallbackLng: 'en',
    referenceLng: 'en',
    whitelist: ['en', 'de'],
    load: 'languageOnly|all' // depending on your whitelist has locals having region like en-US
  }
  */
});

// or
i18next.services.backendConnector.backend.getOptions(callback);

You can set a threshold for languages to be added to whitelist by setting whitelistThreshold in backend options (eg: 1 = 100% translated, 0.9 = 90% translated).

SPECIAL - let the backend determine some options to improve loading

You can load some information from the backend to eg. set whitelist for i18next just supporting languages you got in your locize project.

You will get i18next options for (same as above backend.getOptions):

• fallbackLng
• whitelist
• load

import i18next from 'i18next';
import Backend from 'i18next-node-locize-backend';

const backend = new Backend({
  projectId: '[PROJECTID]',
  apiKey: '[APIKEY]',
  version: '[VERSION]',
  // referenceLng -> not needed as will be loaded from API
}, (err, opts) => {
  i18next
    .use(backend)
    .init({ ...opts, ...yourOptions}); // yourOptions should not include backendOptions!
});

IMPORTANT ADVICE FOR SERVERLESS environments - AWS lambda, Google Cloud Functions, Azure Functions, etc...

Due to how serverless functions work, you cannot guarantee that a cached version of your data is available. Serverless functions are short-lived, and can shut down at any time, purging any in-memory or filesystem cache. This may be an acceptable trade-off, but sometimes it isn't acceptable.

Because of this we suggest to download the translations in your CI/CD pipeline (via cli or via api) and package them with your serverless function.

For example with i18next-node-fs-backend

import i18next from 'i18next';
import Backend from 'i18next-node-fs-backend';

const backend = new Backend({
  // path where resources get loaded from
  loadPath: '/locales/{{lng}}/{{ns}}.json'
});

i18next
  .use(backend)
  .init({ ...opts, ...yourOptions}); // yourOptions should not include backendOptions!

Another example with i18next-sync-fs-backend: here

or just import/require your files directly

import i18next from 'i18next';
import en from './locales/en.json'
import de from './locales/de.json'

i18next
  .init({
    ...opts,
    ...yourOptions,
    resources: {
      en,
      de
    }
  });