move implements and instanceOf methods to inheritance

api/js/etemplate/et2_core_inheritance.ts

@@ -214,4 +214,38 @@ export class ClassWithAttributes
 
 		return attributes;
 	}
+
+	/**
+	 * The implements function can be used to check whether the object
+	 * implements the given interface.
+	 *
+	 * As TypeScript can not (yet) check if an objects implements an interface on runtime,
+	 * we currently implements with each interface a function called 'implements_'+interfacename
+	 * to be able to check here.
+	 *
+	 * @param _iface name of interface to check
+	 */
+	implements (_iface_name : string)
+	{
+		if (typeof window['implements_'+_iface_name] === 'function' &&
+			window['implements_'+_iface_name](this))
+		{
+			return true
+		}
+		return false;
+	}
+
+	/**
+	 * Check if object is an instance of a class or implements an interface (specified by the interfaces name)
+	 *
+	 * @param _class_or_interfacename class(-name) or string with name of interface
+	 */
+	instanceOf(_class_or_interfacename: any) : boolean
+	{
+		if (typeof _class_or_interfacename === 'string')
+		{
+			return this.implements(_class_or_interfacename);
+		}
+		return this instanceof _class_or_interfacename;
+	}
 }