alp-node/src/translate/index.ts

framework based on koa 2

import { Logger } from "nightingale-logger";
import type { AlpNodeApp, Context } from "../AlpNodeApp";
import type { Translations } from "./load";
import load from "./load";

const logger = new Logger("alp:translate");

type Args = Record<string, any>;

export interface TranslateBaseContext {
  t: (id: string, args: Args) => string;
}
export interface TranslateContext {
  readonly language: string;
}

export default function alpTranslate(
  dirname: string,
): (app: AlpNodeApp) => void {
  dirname = dirname.replace(/\/*$/, "/");
  return (app: AlpNodeApp) => {
    const appTranslations = new Map<string, Translations>();

    Object.assign(app.context, {
      t(this: Context, id: string, args: Args): string {
        const msg = appTranslations.get(this.language)?.[id];
        if (!msg) {
          logger.warn("invalid msg", { language: this.language, id });
          return id;
        }

        return msg.format(args) as string;
      },
    });

    const config = app.config;

    config.get<string[]>("availableLanguages").forEach((language) => {
      const translations = app.loadConfigSync(dirname + language);
      appTranslations.set(language, load(translations, language));
    });

    return appTranslations;
  };
}