penx/apps/extension/entrypoints/newtab/appRouterI18n.ts

import 'server-only'
import { I18n, Messages, setupI18n } from '@lingui/core'
import linguiConfig from './lingui.config'

const { locales } = linguiConfig
// optionally use a stricter union type
type SupportedLocales = string

async function loadCatalog(locale: SupportedLocales): Promise<{
  [k: string]: Messages
}> {
  const { messages } = await import(`./locales/${locale}.po`)
  // const messages = {}
  // const { messages } = await import(`@lingui/loader!./locales/${locale}.po`)

  // const { messages } = await (isProd
  //   ? import(`@lingui/loader!./locales/${locale}.po`)
  //   : import(`./locales/${locale}.po`))

  return {
    [locale]: messages,
  }
}

const catalogs = await Promise.all(locales.map(loadCatalog))

// transform array of catalogs into a single object
export const allMessages = catalogs.reduce((acc: any, oneCatalog: any) => {
  return { ...acc, ...oneCatalog }
}, {})

type AllI18nInstances = { [K in SupportedLocales]: I18n }

export const allI18nInstances: AllI18nInstances = locales.reduce(
  (acc: any, locale: string) => {
    const messages = allMessages[locale] ?? {}
    const i18n = setupI18n({
      locale,
      messages: { [locale]: messages },
    })
    return { ...acc, [locale]: i18n }
  },
  {},
)

export const getI18nInstance = (locale: SupportedLocales): I18n => {
  if (!allI18nInstances[locale]) {
    console.warn(`No i18n instance found for locale "${locale}"`)
  }
  return allI18nInstances[locale]! || allI18nInstances['en']!
}