refactor: change meta class structure to include types.

Introduce requiredness of translations via implemented interface.

src/core/things/SportCourse.ts

@@ -12,8 +12,9 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-import {SCEvent, SCEventWithoutReferences} from '../base/Event';
+import {SCEvent, SCEventMeta, SCEventWithoutReferences} from '../base/Event';
 import {SCThingMeta, SCThingType} from '../Thing';
+import {SCMetaTranslations} from '../types/i18n';
 
 /**
  * A sport course without references
@@ -38,13 +39,36 @@ export interface SCSportCourse extends SCEvent, SCSportCourseWithoutReferences {
 }
 
 /**
- * Sport course meta data
+ * Meta information about a sport course
  */
-export class SCSportCourseMeta extends SCThingMeta {
-  static fieldValueTranslations = {
-    ...SCThingMeta.fieldValueTranslations,
+export class SCSportCourseMeta extends SCThingMeta implements SCMetaTranslations<SCSportCourse> {
+  /**
+   * Translations of fields
+   */
+  fieldTranslations = {
     de: {
+      ... SCThingMeta.getInstance().fieldTranslations.de,
+      ... SCEventMeta.getInstance().fieldTranslations.de,
+    },
+    en: {
+      ... SCThingMeta.getInstance().fieldTranslations.en,
+      ... SCEventMeta.getInstance().fieldTranslations.en,
+    },
+  };
+
+  /**
+   * Translations of values of fields
+   */
+  fieldValueTranslations  = {
+    de: {
+      ... SCThingMeta.getInstance().fieldValueTranslations.de,
+      ... SCEventMeta.getInstance().fieldValueTranslations.de,
       type: 'Sportkurs',
     },
+    en: {
+      ... SCThingMeta.getInstance().fieldValueTranslations.en,
+      ... SCEventMeta.getInstance().fieldValueTranslations.en,
+      type: SCThingType.SportCourse,
+    },
   };
 }