feat: add instance getter

application/source/i18n/formatter.mjs

@@ -5,7 +5,7 @@
  * License text available at https://www.gnu.org/licenses/agpl-3.0.en.html
  */
 
-import { internalSymbol } from "../constants.mjs";
+import {instanceSymbol, internalSymbol} from "../constants.mjs";
 import {extend} from "../data/extend.mjs";
 
 import {Formatter as TextFormatter} from "../text/formatter.mjs";
@@ -41,6 +41,15 @@ class Formatter extends TextFormatter {
         this[internalTranslationSymbol] = validateInstance(translation, Translations);
     }
 
+    /**
+     * This method is called by the `instanceof` operator.
+     * @returns {symbol}
+     * @since 3.27.0
+     */
+    static get [instanceSymbol]() {
+        return Symbol.for("@schukai/monster/i18n/formatter@@instance");
+    }
+
     /**
      * @property {object} marker
      * @property {array} marker.open=["i18n{","${"]

application/source/i18n/locale.mjs

@@ -5,6 +5,7 @@
  * License text available at https://www.gnu.org/licenses/agpl-3.0.en.html
  */
 
+import {instanceSymbol} from "../constants.mjs";
 import { Base } from "../types/base.mjs";
 import { validateString } from "../types/validate.mjs";
 import { clone } from "../util/clone.mjs";
@@ -100,6 +101,15 @@ class Locale extends Base {
         this[localeStringSymbol] = s.join("-");
     }
 
+    /**
+     * This method is called by the `instanceof` operator.
+     * @returns {symbol}
+     * @since 3.27.0
+     */
+    static get [instanceSymbol]() {
+        return Symbol.for("@schukai/monster/i18n/locale@@instance");
+    }
+
     /**
      * @return {string}
      */

application/source/i18n/provider.mjs

@@ -5,6 +5,7 @@
  * License text available at https://www.gnu.org/licenses/agpl-3.0.en.html
  */
 
+import {instanceSymbol} from "../constants.mjs";
 import {hasObjectLink, getLinkedObjects,addToObjectLink} from "../dom/attributes.mjs";
 import {getLocaleOfDocument} from "../dom/locale.mjs";
 import {BaseWithOptions} from "../types/basewithoptions.mjs";
@@ -32,6 +33,16 @@ const translationsLinkSymbol = Symbol.for("@schukai/monster/i18n/translations@@l
  * @see {@link https://datatracker.ietf.org/doc/html/rfc3066}
  */
 class Provider extends BaseWithOptions {
+
+    /**
+     * This method is called by the `instanceof` operator.
+     * @returns {symbol}
+     * @since 3.27.0
+     */
+    static get [instanceSymbol]() {
+        return Symbol.for("@schukai/monster/i18n/provider@@instance");
+    }    
+    
     /**
      * @param {Locale|string} locale
      * @return {Promise}

application/source/i18n/translations.mjs

@@ -5,6 +5,7 @@
  * License text available at https://www.gnu.org/licenses/agpl-3.0.en.html
  */
 
+import {instanceSymbol} from "../constants.mjs";
 import {getLinkedObjects, hasObjectLink} from "../dom/attributes.mjs";
 import {ATTRIBUTE_OBJECTLINK} from "../dom/constants.mjs";
 import {getDocument} from "../dom/util.mjs";
@@ -44,6 +45,15 @@ class Translations extends Base {
         this.storage = new Map();
     }
 
+    /**
+     * This method is called by the `instanceof` operator.
+     * @returns {symbol}
+     * @since 3.27.0
+     */
+    static get [instanceSymbol]() {
+        return Symbol.for("@schukai/monster/i18n/translations@@instance");
+    }
+
     /**
      * Fetches a text using the specified key.
      * If no suitable key is found, `defaultText` is taken.
@@ -107,9 +117,11 @@ class Translations extends Base {
             return validateString(r[keyword]);
         }
 
-        if (r.hasOwnProperty(DEFAULT_KEY)) {
-            return validateString(r[DEFAULT_KEY]);
-        }
+        // @deprecated since 2023-03-14
+        // DEFAULT_KEY is undefined
+        // if (r.hasOwnProperty(DEFAULT_KEY)) {
+        //     return validateString(r[DEFAULT_KEY]);
+        // }
 
         return validateString(defaultText);
     }