Author:
    Aymeric PINEAU
    Creation:2026-08-24Last update:2026-08-24

    elysia-intlayer Package

    The elysia-intlayer package provides a plugin for Elysia applications to handle internationalization. It detects the user's locale and injects an intlayer object into the route context.

    Installation

    bash
    npm install intlayer elysia-intlayer
    elysia is a peer dependency (>=1.0.0). Elysia targets the Bun runtime.

    Exports

    Plugin

    Import:

    ts
    import { intlayer } from "elysia-intlayer";
    Function Description Related Doc
    intlayer Elysia plugin that integrates Intlayer into your Elysia application. Handles locale detection from storage (cookie, header) then from Accept-Language, injects an intlayer object exposing locale, t, getIntlayer and getDictionary into the route context, and sets up the AsyncLocalStorage request context. intlayer

    Functions

    Import:

    ts
    import { t, getIntlayer, getDictionary } from "elysia-intlayer";
    Function Description Related Doc
    t Global translation function that retrieves content for the current locale in Elysia. Uses AsyncLocalStorage to access the request context set up by the intlayer plugin, and falls back to the default locale outside of it. Can also be accessed via intlayer.t. translation
    getIntlayer Retrieves a dictionary by its key from the generated declaration and returns its content for the current locale. Optimized version of getDictionary. Uses AsyncLocalStorage to access the request context. Can also be accessed via intlayer.getIntlayer. -
    getDictionary Processes dictionary objects and returns content for the current locale. Processes t() translations, enumerations, markdown, HTML, etc. Uses AsyncLocalStorage to access the request context. Can also be accessed via intlayer.getDictionary. -

    Types

    Import:

    ts
    import type { IntlayerContext, TranslateFunction } from "elysia-intlayer";
    Type Description
    IntlayerContext Shape of the intlayer object injected into every route context: locale, locale_storage, locale_detected, defaultLocale, t, getIntlayer, getDictionary.
    TranslateFunction Signature of the translation function, translating a locale map into the content matching the current request locale.

    Usage

    src/index.ts
    import { Elysia } from "elysia";
import { getDictionary, getIntlayer, intlayer, t } from "elysia-intlayer";
import dictionaryExample from "./index.content";

const app = new Elysia()
  // Load the internationalization plugin
  .use(intlayer())
  // Read the locale and the helpers from the route context
  .get("/", ({ intlayer }) => ({
    locale: intlayer!.locale,
    greeting: intlayer!.t({
      en: "Hello",
      fr: "Bonjour",
      es: "Hola",
    }),
    content: intlayer!.getIntlayer("index").exampleOfContent,
  }))
  // Or use the standalone helpers, bound to the current request
  .get("/t_example", () =>
    t({
      en: "Example of returned content in English",
      fr: "Exemple de contenu renvoyé en français",
      es: "Ejemplo de contenido devuelto en español",
    })
  )
  .get("/getIntlayer_example", () => getIntlayer("index").exampleOfContent)
  .get(
    "/getDictionary_example",
    () => getDictionary(dictionaryExample).exampleOfContent
  )
  .listen(3000);

console.log(
  `🦊 Elysia is running at ${app.server?.hostname}:${app.server?.port}`
);
    The plugin registers its context through a global derive, which Elysia types as Partial<{ intlayer: IntlayerContext }>. The value is always present at runtime for routes registered after .use(intlayer()), so use the non-null assertion (intlayer!.locale) — or optional chaining — to satisfy TypeScript in strict mode.

    Related Doc

    intlayerintlayer