i18next-slavic

Typed Slavic-case (declension) helper for react-i18next, plus a small CLI that generates fully-typed resource definitions from your locale JSON.

Slavic languages (Russian, Ukrainian, Polish, …) inflect nouns across six grammatical cases. i18next-slavic maps each case to an i18next context, so you keep one translation key and let i18next pick the right form — with full TypeScript autocomplete on your keys.

Install

npm install @dmhd6219/i18next-slavic
# peers (you almost certainly already have these):
npm install i18next react-i18next react

The hook

import { useSlavicTranslation } from '@dmhd6219/i18next-slavic';

function Greeting() {
  const { tCase, t } = useSlavicTranslation('common');

  return (
    <p>
      {/* "Добро пожаловать в Москву" — resolved from `city_accusative` */}
      Добро пожаловать в {tCase('city', 'accusative')}
    </p>
  );
}

useSlavicTranslation is a thin wrapper over useTranslation and returns the usual { t, i18n, ready } plus:

tCase(
  key: TranslationKey,          // typed from your own resources
  wordCase: SlavicCase,         // 'nominative' | 'genitive' | 'dative' | …
  options?: TOptions,
  defaultValue?: string,
): string

SlavicCase covers all six cases:

type SlavicCase =
  | 'nominative'
  | 'genitive'
  | 'dative'
  | 'accusative'
  | 'instrumental'
  | 'prepositional';

Locale JSON

Provide one base key plus a context-suffixed variant per case:

{
  "city": "Москва",
  "city_genitive": "Москвы",
  "city_dative": "Москве",
  "city_accusative": "Москву",
  "city_instrumental": "Москвой",
  "city_prepositional": "Москве"
}

The CLI

The bundled i18next-slavic command scans your locale JSON and writes a typed Resources interface plus the i18next module augmentation that powers autocomplete in the hook.

npx @dmhd6219/i18next-slavic --locales public/locales/ru --out src/@types/resources.d.ts

After installing, the local bin is exposed as i18next-slavic, so inside an npm script you can call it directly (see below).

| Option | Alias | Default | Description | | ------ | ----- | ------- | ----------- | | --locales <dir> | -l | public/locales/ru | Locale folder to read | | --out <file> | -o | src/@types/resources.d.ts | Output .d.ts file | | --default-ns <ns> | -n | common | defaultNS written into i18next.d.ts | | --cwd <dir> | -c | auto-detected | Project root | | --help | -h | | Show help |

It writes two files:

• <out> — the Resources interface, regenerated on every run.
• <out-dir>/i18next.d.ts — the i18next augmentation, created once and then left untouched so your manual tweaks survive.

Add it to your scripts so types stay in sync:

{
  "scripts": {
    "i18n:types": "i18next-slavic"
  }
}

Context/plural variants (keys containing _) are intentionally excluded from the generated key union — you reference the base key and pass the case to tCase.

License

MIT