Merge pull request ghidoz#224 from hpawe01/fix/support-relationship-r…

…emoval

Allow removal of HasMany relations by setting empty array

src/services/json-api-datastore.service.spec.ts

@@ -660,5 +660,27 @@ describe('JsonApiDatastore', () => {
         }
       });
     });
+
+    it('should remove empty ToMany-relationships', () => {
+      const expectedUrl = `${BASE_URL}/${API_VERSION}/authors/${AUTHOR_ID}`;
+      const BOOK_NUMBER = 2;
+      const DATA = getAuthorData('books', BOOK_NUMBER);
+      const author = new Author(datastore, DATA);
+
+      author.books = [];
+
+      author.save().subscribe();
+
+      httpMock.expectNone(`${BASE_URL}/${API_VERSION}/authors`);
+      const saveRequest = httpMock.expectOne({ method: 'PATCH', url: expectedUrl });
+      const obj = saveRequest.request.body.data;
+      expect(obj.relationships).toBeDefined();
+      expect(obj.relationships.books).toBeDefined();
+      expect(obj.relationships.books.data).toBeDefined();
+      expect(obj.relationships.books.data.length).toBe(0);
+
+      saveRequest.flush({});
+
+    });
   });
 });

src/services/json-api-datastore.service.ts

@@ -232,7 +232,7 @@ export class JsonApiDatastore {
               data: this.buildSingleRelationshipData(data[key])
             };
           }
-        } else if (data[key] instanceof Array && data[key].length > 0) {
+        } else if (data[key] instanceof Array) {
           const entity = hasManyMetadata.find((entity: any) => entity.propertyName === key);
           if (entity && this.isValidToManyRelation(data[key])) {
             relationships = relationships || {};
@@ -254,6 +254,9 @@ export class JsonApiDatastore {
   }
 
   protected isValidToManyRelation(objects: Array<any>): boolean {
+    if (!objects.length) {
+      return true;
+    }
     const isJsonApiModel = objects.every((item) => item instanceof JsonApiModel);
     if (!isJsonApiModel) {
       return false;