Class I18n

src/i18n.ts:7–89

type TranslationValues = Record<string, string | number>;

class I18n {
  private currentLocale: 'zh' | 'en' = 'en';
  private translations = {
    zh: zhTranslations,
    en: enTranslations,
  };

  /**
   * Set locale directly
   * @param locale - 'zh' or 'en'
   */
  setLocale(locale: 'zh' | 'en') {
    this.currentLocale = locale;
  }

  /**
   * Get current locale
   */
  getLocale(): 'zh' | 'en' {
    return this.currentLocale;
  }

  /**
   * Translate a key with optional interpolation
   * @param key - Translation key
   * @param values - Values for interpolation (optional)
   * @returns Translated string with interpolated values
   */
  t(key: TranslationKey, values?: TranslationValues): string {
    const translation =
      this.translations[this.currentLocale][
        key as keyof (typeof this.translations)[typeof this.currentLocale]
      ];

    if (!translation) {
      // Fallback to the other locale if key not found
      const fallbackLocale = this.currentLocale === 'zh' ? 'en' : 'zh';
      const fallbackTranslation =
        this.translations[fallbackLocale][
          key as keyof (typeof this.translations)[typeof fallbackLocale]
        ];

      if (!fallbackTranslation) {
        // If still not found, return the key itself
        return String(key);
      }

      return this.interpolate(fallbackTranslation, values);
    }

    return this.interpolate(translation, values);
  }

  /**
   * Interpolate values into a string template
   * Supports {{key}} syntax
   * @param template - String template with {{key}} placeholders
   * @param values - Values to interpolate