feat: add ExtractLanguages helper

README.md

@@ -56,6 +56,12 @@ const bot = new Bot(process.env.BOT_TOKEN as string)
     });
 ```
 
+`ExtractLanguages` helps you extract languages types from i18n instance.
+
+```ts
+type EnLocalizationKeys = keyof ExtractLanguages<typeof i18n>["en"];
+```
+
 ## [Fluent](https://projectfluent.org/) syntax
 
 This plugin provide internationalization for your bots with [Fluent](https://projectfluent.org/) syntax.

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@gramio/i18n",
-	"version": "1.0.0",
+	"version": "1.0.1",
 	"description": "i18n plugin for GramIO with type-safety",
 	"main": "dist/index.cjs",
 	"module": "dist/index.js",

src/index.ts

@@ -1,20 +1,13 @@
 import type {
 	ExtractArgsParams,
 	ExtractItemValue,
+	I18nOptions,
 	LanguagesMap,
 	SoftString,
 } from "./types.js";
 
 export * from "./types.js";
 
-export interface I18nOptions<
-	Languages extends LanguagesMap,
-	PrimaryLanguage extends keyof Languages,
-> {
-	languages: Languages;
-	primaryLanguage: PrimaryLanguage;
-}
-
 export function defineI18n<
 	Languages extends LanguagesMap,
 	PrimaryLanguage extends keyof Languages,
@@ -79,6 +72,10 @@ export function defineI18n<
 					: ExtractArgsParams<Item>
 			): ExtractItemValue<Item, FallbackItem> => t(language, key, ...args);
 		},
+		_: {
+			languages,
+			primaryLanguage,
+		},
 		// plugin: () => {},
 	};
 }

src/types.ts

@@ -40,3 +40,17 @@ export type ShouldFollowLanguageStrict<Language extends LanguageMap> = {
 };
 
 export type SoftString<Strings> = Strings | ({} & string);
+
+export interface I18nOptions<
+	Languages extends LanguagesMap,
+	PrimaryLanguage extends keyof Languages,
+> {
+	languages: Languages;
+	primaryLanguage: PrimaryLanguage;
+}
+
+export type ExtractLanguages<T> = T extends {
+	_: { languages: infer Languages };
+}
+	? Languages
+	: never;

tests/index.test.ts

@@ -1,14 +1,24 @@
 import { describe, expect, it } from "bun:test";
 import { Bot, format } from "gramio";
 import { defineI18n } from "../src";
-import type { ShouldFollowLanguage } from "../src/types";
+import type { ExtractLanguages, ShouldFollowLanguage } from "../src/types";
 
 const en = {
 	greeting: (name: string) => format`Hello, ${name}!`,
 };
 
 const ru: ShouldFollowLanguage<typeof en> = {};
 
+const i18n1 = defineI18n({
+	languages: {
+		en,
+		ru,
+	},
+	primaryLanguage: "en",
+});
+
+type A = ExtractLanguages<typeof i18n1>["en"];
+
 describe("I18n", () => {
 	it("Just t", () => {
 		const i18n = defineI18n({