TypeScript + i18n done properly

All source in i18n/

• Absolute type safety, no more "translation.common.app.name"
• Works with TypeScript 4.9+
• Requires no interaction with fs or fetch. All done by your bundler/runtime
• Caches loaded locales.
• No codegen

Example (Next.JS)

// @/i18n/locales/en/index.ts

export const en = {
  hello: "Hello world!"
}

// pages/index.tsx
import { loadLocale, checkLocale } from "@/i18n";
import type { GetStaticProps, InferGetStaticPropsType } from "next"

export function getStaticProps({ locale }) {
  return {
    props: {
      translation: await loadLocale(checkLocale(locale))
    }
  }
} satisfies GetStaticProps;

export function Home({ translation }: InferGetStaticPropsType<typeof getStaticProps>) {
  return <h1>{translation.hello}</h1>;
  //                      ^? (property) hello: string 
}