132 bytes i18n in Nuxt.js

utils.ts

// export function useI18n(translations) {
//   return (key, ...args) => {
//     const value = key.trim().split('.').reduce((obj, k) => obj?.[k], translations) ?? key
//     return typeof value === 'function' ? value(...args) : value
//   }
// }
export function useI18n(t){return(n,...e)=>{const r=n.trim().split('.').reduce(((t,n)=>t?.[n]),t)??n;return'function'==typeof r?r(...e):r}}
export const t = (x, y) => useRoute().meta.t(x, y)

Usage

export default defineNuxtRouteMiddleware(async (to) => {
  const { lang } = to.params
  const isLang = ['sr', 'de'].includes(lang)
  const filename = isLang ? lang : 'en'
  const { default: i18n } = await import(`./../i18n/${to.name}/${filename}.js`)
  // DE
  // {
  //  welcome: 'Willkommen!',
  //  hello: x => `Hallo ${x}!`,
  //  colors: [
  //    'Weiß',
  //    'Schwarz'
  //  ]
  // }
  to.meta = { t: useI18n(i18n) }
})

<script setup>
// No imports; Magic 🪄
</script>

<template>
{{ t('welcome') }}   <!-- Willkommen! -->
{{ t('hello', 'Dalibor') }}  <!-- Hallo Dalibor! -->
{{ t('colors.1') }}  <!-- Schwarz -->
</template>