在 Azure 函数中初始化 i18next

Question

I have an azure http trigger function, which is called by a client with some data and client's culture string eg "en-US". index.js handles the azure request. myWorker.js has a function doStuff() which prepares data to return to the client. I am using i18next for localizations.

index.js needs to pass the culture string to i18next. It seems logical to put i18next in myWorker.js but it needs to load before index.js calls the doStuff function. Forgive me if this is a mess but I'm new to node and don't know the best way to set it up.

How does index.js pass the culture string to myworker.js, wait for i18next to load, pass the main data to dostuff() and finish with context.done()?

index.js
module.exports = async function (context, req) {
    switch (req.body.data.action) {
        case 'doWork':
            let myworker = require('./myWorker')(req.body.data.culture)  //culture string for i18next
            let retval = myworker.dostuff();  //i18next fails as it isn't loaded yet.
            context.res = {
                status: 200, body: {someData: retval}
            };
            break;
        case 'anotherCommand':
        ....
    }
    context.done();
}

myWorker.js
let i18next = require("i18next");
let backend = require("i18next-node-fs-backend");

function dostuff() {
     calc some stuff using i18next.t(key);
}

function setup_i18next(cultr) {
    i18next
        .use(backend)
        .init({
            fallbackLng: 'en',
            lng: cultr,
            backend: {
                loadPath: 'locales/{{lng}}/{{ns}}.json'
            },
            ns: ['myspace1', 'myspace2']
        })
        .then(function (t) {
            ????
         });
}

module.exports = function(cultre) {
    setup_i18next(cultre);
    return {
        dostuff
    }
}

Answer 1

Use fs-backend, like this:

// i18n.js
const { join } = require('path')
const { readdirSync, lstatSync } = require('fs')
const i18next = require('i18next')
const Backend = require('i18next-fs-backend')
i18next
  .use(Backend)
  .init({
    // debug: true,
    initImmediate: false, // setting initImediate to false, will load the resources synchronously
    fallbackLng: 'en',
    lng: 'en',
    preload: readdirSync(join(__dirname, '../locales')).filter((fileName) => {
      const joinedPath = join(join(__dirname, '../locales'), fileName)
      const isDirectory = lstatSync(joinedPath).isDirectory()
      return isDirectory
    }),
    ns: 'backend-app',
    defaultNS: 'backend-app',
    backend: {
      loadPath: join(__dirname, '../locales/{{lng}}/{{ns}}.json')
    }
  })
module.exports = (lng) => i18next.getFixedT(lng || 'en')

Then just use it like this:

const t = require('../i18n')(lng)
const title = t('invitation.subject')

Answer 2

Based on @adrai's answer (which I never would have figured out) I think it can be tweaked to specify the language in the init. Otherwise, we'd unnecessarily load the 'en' translations if another language is specified via lang.

const { join } = require('path')
const { readdirSync, lstatSync } = require('fs')
const i18next = require('i18next')
const SyncBackend = require('i18next-sync-fs-backend')

module.exports = (lang) => {
  i18next
  .use(SyncBackend)
  .init({
    // debug: true,
    initImmediate: false,
    fallbackLng: 'en',
    lng:lang,
    preload: readdirSync(join(__dirname, '../locales')).filter((fileName) => {
      const joinedPath = join(join(__dirname, '../locales'), fileName)
      const isDirectory = lstatSync(joinedPath).isDirectory()
      return isDirectory
    }),
    ns: ['k2locals','sfaDebugger'],
    defaultNS: 'k2locals',
    debug: true,
    backend: {
      loadPath: join(__dirname, '../locales/{{lng}}/{{ns}}.json')
    }
  })
  return i18next.getFixedT(lang || 'en', 'k2locals')
}