fluent2ts

Fluent is an great DSL for localization. This project allows you to generate TypeScript types for yours .ftl files.

Usage

Npm:

npx fluent2ts

Bun:

bunx fluent2ts

Yarn:

yarn dlx fluent2ts

Pnpm:

pnpm exec fluent2ts

After that, the locales.types.ts file is automatically generated in the src folder. You can also change this path by specifying the -o (or --output) argument. For example - npx fluent2ts -o src/some/i18n.ts.

You can also specify the glob pattern to search for .ftl files are specified after the command. For example npx fluent2ts locales/**/*.ftl. By default it is **/*.ftl.

Watch mode

You can also use watch mode and regenerate the types when the file has been modified. To do this, simply specify the --watch (or -w) argument. For example, npx fluent2ts -w.

Output

For example for this:

# 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
    }.

The following will be generated:

import type {
    FluentBundle,
    FluentVariable,
    Message as FluentMessage,
    // @ts-ignore
} from "@fluent/bundle";

export interface LocalesMap {
    "hello-user": {
        userName: FluentVariable;
    };
    "shared-photos": {
        userName: FluentVariable;
        photoCount: FluentVariable;
        userGender: FluentVariable;
    };
}

export interface Message<Key extends keyof LocalesMap> extends FluentMessage {
    id: Key;
}

export interface TypedFluentBundle extends FluentBundle {
    getMessage<Key extends keyof LocalesMap>(key: Key): Message<Key>;
    formatPattern<Key extends keyof LocalesMap>(
        key: Key,
        ...args: LocalesMap[Key] extends never ? [] : [args: LocalesMap[Key]]
    ): string;
    formatPattern<Key extends keyof LocalesMap>(
        key: Key,
        args: LocalesMap[Key] extends never ? null : LocalesMap[Key],
        errors?: Error[] | null
    ): string;
}