@gramio/i18n

i18n plugin for GramIO.

This plugin provide good way to add internationalization for your bots! It can be used without GramIO, but it will always keep it in mind.

Important

Since 1.0.0, we have two ways to write localization: I18n-in-TS and Fluent

I18n-in-TS syntax

This syntax allows you to write localization without leaving .ts files and does not require code-generation for type-safety, as well as provides convenient integration with the Format API out of the box!

import {
    defineI18n,
    type LanguageMap,
    type ShouldFollowLanguage,
} from "@gramio/i18n";

const en = {
    greeting: (name: string) => format`Hello, ${name}!`,
} satisfies LanguageMap;

const ru = {
    greeting: (name: string) => format`Привет, ${name}!`,
} satisfies ShouldFollowLanguage<typeof en>;

// Strict will show error on missing keys
// satisfies ShouldFollowLanguageStrict<typeof en>;

const i18n = defineI18n({
    primaryLanguage: "en",
    languages: {
        en,
        ru,
    },
});

i18n.t("en", "greeting", "World"); // Hello, World!

const bot = new Bot(process.env.BOT_TOKEN as string)
    .derive("message", (context) => {
        // u can take language from database or whatever u want and bind it to context without loosing type-safety
        return {
            t: i18n.buildT(context.from?.languageCode ?? "en"),
        };
    })
    .on("message", (context) => {
        return context.send(
            context.t("greeting", context.from?.firstName ?? "World")
        );
    });

ExtractLanguages helps you extract languages types from i18n instance.

type EnLocalization = ExtractLanguages<typeof i18n>["en"];
type EnLocalizationKeys = keyof ExtractLanguages<typeof i18n>["en"];

type EnGreetingArgs = ExtractArgsParams<EnLocalization["greeting"]>;

Fluent syntax

This plugin provide internationalization for your bots with Fluent syntax.

You can setup type-safety for it.

Usage

Create locales folder with en.ftl file

# Simple things are simple.
hello-user = Hello, {$userName}!

# Complex things are possible.
shared-photos =
    {$userName} {$photoCount ->
        [one] added a new photo
       *[other] added {$photoCount} new photos
    } to {$userGender ->
        [male] his stream
        [female] her stream
       *[other] their stream
    }.

Important

Fluent language support extensions for VSCode and WebStorm

Use plugin

// src/index.ts
import { Bot } from "gramio";
import { i18n } from "@gramio/i18n/fluent";

const bot = new Bot(process.env.TOKEN as string)
    .extend(i18n())
    .command("start", async (context) => {
        return context.send(
            context.t("shared-photos", {
                userName: "Anna",
                userGender: "female",
                photoCount: 3,
            })
        );
    })
    .onError(console.error)
    .onStart(console.log);

bot.start();

Options

Key	Type	Default	Description
defaultLocale?	string	first loaded language	Default locale
directory?	string	"locales"	The path to the folder with *.ftl files

Methods

t

Using this method, you can get the text in your chosen language.

For example:

hello-user = Hello, {$userName}!

context.t("hello-user", { userName: "Anna" }); // Hello, Anna!

i18n.setLocale

You can set user locale by setLocale method.

Warning

At the moment, there is no integration with sessions, and therefore, after the message, the language will again become the one that defaultLocale

bot.command("start", async (context) => {
    context.i18n.setLocale("ru"); // if ru not found fallback to defaultLocale
    // context.i18n.setLocale("ru", true); if ru not found throw error

    return context.send(
        context.t("shared-photos", {
            userName: "Anna",
            userGender: "female",
            photoCount: 3,
        })
    );
});

i18n.locale

Get current user locale.

bot.command("lang", async (context) => {
    return context.send(context.i18n.locale);
});

i18n.locales

Get loaded locales

bot.command("languages", async (context) => {
    return context.send(context.i18n.locales.join(", "));
});

Type-safety

You can use this plugin with fluent2ts which code-generates typescript types from your .ftl files. See usage.

Npm:

npx fluent2ts

Bun:

bunx fluent2ts

Yarn:

yarn dlx fluent2ts

Pnpm:

pnpm exec fluent2ts

And so we have a generated locales.types.ts file in src folder that exports the TypedFluentBundle interface. We set this type as a generic for the i18n plugin. And now we have type-safety!

import type { TypedFluentBundle } from "./locales.types";
import { Bot } from "gramio";
import { i18n } from "@gramio/i18n/fluent";

const bot = new Bot(process.env.TOKEN as string)
    .extend(i18n<TypedFluentBundle>())
    .command("start", async (context) => {
        return context.send(
            context.t("shared-photos", {
                userName: "Anna",
                userGender: "female",
                photoCount: 3,
            })
        );
    })
    .onError(console.error)
    .onStart(console.log);

bot.start();