@telefonica/la-content-i18n

Library to handle localization in React apps.

$ npm install @telefonica/la-content-i18n

Usage

1. Wrap your component tree in a <I18nProvider>, with the i18n attribute set to the instance resulting from init().

   languageImporter is an async function called successively with locale and namespace names. It's your responsibility to load the .json files with translations given these. It is okay to return a failing Promise if the .json file can't be found.

   import { init, I18nProvider } from '@telefonica/la-content-i18n'
   
   const i18n = init({
     languageImporter: async (locale, namespace) => import(`../locales/${locale}/${namespace}.json`),
   })
   
   export const AppWrapper = ({ children }) => <I18nProvider i18n={i18n}>{children}</I18nProvider>

   Translations will be layered. Basically, the finished strings would be something like:

   const translations = {
     ...(await languageImporter('dev', ns)),
     ...(await languageImporter('en', ns)),
     ...(await languageImporter('en-US', ns)),
   }

2. Throughout your app, wrap any translatable strings in the <Trans> component, with an i18nKey prop identifying said string. You can also call the useTranslation() hook and the t() function it returns.

   import { Trans } from '@telefonica/la-content-i18n'
   import { MyHoverEffect } from './other-components'
   
   const MyHeader = () => (
     <div>
       <h1>
         {/* Basic usage */}
         <Trans i18nKey="myheader.welcome">Hello world!</Trans>
       </h1>
       <p>
         {/* This works! The string will reflect simple tags in the translatable messages. */}
         <Trans i18nKey="myheader.subtitle">
           Welcome to the <b>best</b> app in the world.
         </Trans>
       </p>
       <p>
         {/* This still works. More complex elements will be anonymized and be shown like `<0>this</0>`. */}
         <Trans i18nKey="myheader.call-to-action">
           Learn more about us <MyHoverEffect>now!</MyHoverEffect>
         </Trans>
       </p>
       <p>
         {/* Yep, still works! Wrap variables in an object to have it be shown as an identifier in the translatable messages. */}
         <Trans i18nKey="myheader.current-user">You're currently logged in as {{ name }}.</Trans>
       </p>
     </div>
   )

   If the <Trans> component is not enough (e.g. you need plurals), you can access a full i18next instance calling the useTranslation() hook.

3. Call the bundled i18n binary to extract the strings from the source files. Use the -l parameter to pass a list of the desired locales.

   The default source file glob is src/**.{js,jsx,ts,tsx,mjs,cjs}, and the default output path is locales/{{locale}}/{{ns}}.json.

   $ npx i18n extract -l en,es

4. Translate the extracted .json files

5. Done!

Detect/change locale

With the i18n instance resulting from init() or the useTranslation() hook, you can call i18n.changeLanguage("locale"). If you don't pass a locale, one will be detected from the user's browser.

Architecture

This library is a wrapper on top of i18next and react-i18next, with some options already set by default. You can read their documentation to learn more about how it works.

This wrapper:

• Initializes i18next and react-i18next (./src/index.ts):

  • with the browser-based language detector
  • with a custom manual backend (./src/ManualBackend.ts) that just calls a user-provided function

    Why? So the caller of the API can import() the translation files and have them handled by their bundler (i.e. webpack).

  • with automatic debugging for production
  • some more useful options (check i18next options documentation )

• Re-exports react-i18next interfaces <Trans> and useTranslation() (the rest are not useful for our usecase) (./src/react.sx)

• Provides a CLI for extracting translations from code into the locale files (through babel-plugin-i18next-extract) (./src/bin.ts):

  • It manually runs babel with the babel-plugin-i18next-extract plugin on the specified files, already prepared to accept the re-exported entrypoints from this package.