fix(graphql): column with complex object could throw null pointer exc…

…eption (#1130)

* Pass in undefined (instead of null) so TypeScript uses the default value in the parameter signature

* fix linting, null coalesce to {}

---------

Co-authored-by: Ronald Van Ryswyk <ronald.van.ryswyk@positivecircularity.com>

packages/graphql/src/services/__tests__/graphql.service.spec.ts

@@ -416,6 +416,15 @@ describe('GraphqlService', () => {
 
       expect(removeSpaces(query)).toBe(removeSpaces(expectation));
     });
+
+    it('should return a query string including a direct reference to a complex object', () => {
+      const expectation = `firstName, lastName, billing{address{street, zip}}`;
+      const columns = ['firstName', 'lastName', 'billing', 'billing.address.street', 'billing.address.zip'];
+
+      const query = service.buildFilterQuery(columns);
+
+      expect(removeSpaces(query)).toBe(removeSpaces(expectation));
+    });
   });
 
   describe('clearFilters method', () => {

packages/graphql/src/services/graphql.service.ts

@@ -195,7 +195,7 @@ export class GraphqlService implements BackendService {
 
     const set = (o: any = {}, a: any) => {
       const k = a.shift();
-      o[k] = a.length ? set(o[k], a) : null;
+      o[k] = a.length ? set(o[k] ?? {}, a) : null;
       return o;
     };
 

packages/graphql/src/services/graphqlQueryBuilder.ts

@@ -5,7 +5,7 @@
  *
  * The previous lib can be found here at this Github link:
  *     https://github.com/codemeasandwich/graphql-query-builder
- * his licence is MIT and can be found at 
+ * This licence is MIT and can be found at
  *     https://github.com/codemeasandwich/graphql-query-builder/blob/master/LICENSE
  */
 export default class GraphqlQueryBuilder {