Internationalization for Elysia

🌟 Features

✅️️  Internationalization utilities: support internationalization utils via @intlify/utils

✅️  Translation: Simple API like vue-i18n

✅  Custom locale detector: You can implement your own locale detector on server-side

💿 Installation

# Using npm
npm install @intlify/elysia

# Using yarn
yarn add @intlify/elysia

# Using pnpm
pnpm add @intlify/elysia

# Using bun
bun add @intlify/elysia

🚀 Usage

Detect locale with utils

Detect locale from accept-language header:

import { Elysia } from 'elysia'
import { getHeaderLocale } from '@intlify/elysia'

new Elysia().get('/', ctx => {
  // detect locale from HTTP header which has `Accept-Language: ja,en-US;q=0.7,en;q=0.3`
  const locale = getHeaderLocale(ctx.request)
  return locale.toString()
})

Detect locale from URL query:

import { Elysia } from 'elysia'
import { getQueryLocale } from '@intlify/elysia'

new Elysia().get('/', ctx => {
  // detect locale from query which has 'http://localhost:3000?locale=en'
  const locale = getQueryLocale(ctx.request)
  return locale.toString()
})

Translation

+If you want to use translation, you need to install plugin. As a result, locale property and translation function will be extended in Elysia Context:

import { Elysia } from 'elysia'
import { detectLocaleFromAcceptLanguageHeader, intlify } from '@intlify/elysia'

const app = new Elysia()
  .use(
    // configure plugin options like vue-i18n
    intlify({
      // detect locale with `accept-language` header
      locale: detectLocaleFromAcceptLanguageHeader,
      // resource messages
      messages: {
        en: {
          hello: 'hello, {name}'
        },
        ja: {
          hello: 'こんにちは, {name}'
        }
      }
      // something options
      // ...
    })
  )
  .get('/', ctx => {
    // use `locale` property in handler
    console.log('current locale', ctx.locale)
    // use `translation` function in handler
    return ctx.translate('hello', { name: 'elysia' })
  })

export default app

🛠️ Custom locale detection

You can detect locale with your custom logic from current Context.

example for detecting locale from url query:

import { Elysia } from 'elysia'
import { getQueryLocale, intlify } from '@intlify/elysia'

import type { Context } from 'elysia'

const DEFAULT_LOCALE = 'en'

// define custom locale detector
const localeDetector = (ctx: Context): string => {
  try {
    return getQueryLocale(ctx.request).toString()
  } catch {
    return DEFAULT_LOCALE
  }
}

new Elysia().use(
  intlify({
    // set your custom locale detector
    locale: localeDetector
    // something options
    // ...
  })
)

You can make that function asynchronous. This is useful when loading resources along with locale detection.

[!NOTE] The case which a synchronous function returns a promise is not supported. you need to use async function.

import { Elysia } from 'elysia'
import { intlify, getCookieLocale } from '@intlify/elysia'

import type { Context } from 'elysia'
import type { DefineLocaleMessage, CoreContext } from '@intlify/elysia'

// loader for resources
const loader = (path: string) => import(path, { with: { type: 'json' } }).then(m => m.default)
const messages: Record<string, () => ReturnType<typeof loader>> = {
  en: () => loader('./locales/en.json'),
  ja: () => loader('./locales/ja.json')
}

// define custom locale detector and lazy loading
const localeDetector = async (
  ctx: Context,
  intlify: CoreContext<string, DefineLocaleMessage>
): Promise<string> => {
  // detect locale
  const locale = getCookieLocale(ctx.request).toString()

  // resource lazy loading
  const loader = messages[locale]
  if (loader && !intlify.messages[locale]) {
    const message = await loader()
    intlify.messages[locale] = message
  }

  return locale
}

new Elysia().use(
  intlify({
    // set your custom locale detector
    locale: localeDetector
    // something options
    // ...
  })
)

🖌️ Resource keys completion

resource keys completion has twe ways.

Type parameter for intlify plugin

[!NOTE] The example code is here

You can set the type parameter of intlify plugin to the resource schema you want to key completion of the translation function.

the part of example:

type ResourceSchema = {
  hello: string
}

new Elysia()
  .use(
    // you can put the type extending with type argument of plugin as locale resource schema
    intlify<ResourceSchema>({
      // something options ...
    })
  )
  .get('/', ctx => {
    // you can completion when you type `ctx.translate('`
    return ctx.translate('hi', { name: 'elysia' })
  })

global resource schema with declare module '@intlify/elysia'

[!NOTE] The exeample code is here

You can do resource key completion with the translation function using the typescript declare module.

the part of example:

import en from './locales/en.ts'

// 'en' resource is master schema
type ResourceSchema = typeof en

// you can put the type extending with `declare module` as global resource schema
declare module '@intlify/elysia' {
  // extend `DefineLocaleMessage` with `ResourceSchema`
  export interface DefineLocaleMessage extends ResourceSchema {}
}

new Elysia()
  .use(
    intlify({
      // something options ...
    })
  )
  .get('/', ctx => {
    // you can completion when you type `ctx.translate('`
    return ctx.translate('hello', { name: 'elysia' })
  })

The advantage of this way is that it is not necessary to specify the resource schema in the plugin intlify.

🛠️ Utilities & Helpers

@intlify/elysia has a concept of composable utilities & helpers.

See the API References

🙌 Contributing guidelines

If you are interested in contributing to @intlify/elysia, I highly recommend checking out the contributing guidelines here. You'll find all the relevant information such as how to make a PR, how to setup development etc., there.

🤝 Sponsors

The development of srvmid is supported by my OSS sponsors!

©️ License

MIT