fix(graphql,federation,doug-martin#1051): return null for references

mwoelk · Apr 8, 2021 · a4f3475 · a4f3475
1 parent 70fd48e
commit a4f3475
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/packages/query-graphql/src/decorators/reference.decorator.ts b/packages/query-graphql/src/decorators/reference.decorator.ts
@@ -6,14 +6,14 @@ import { BaseResolverOptions } from './resolver-method.decorator';
 import { mergeBaseResolverOpts } from '../common';
 
 const reflector = new ArrayReflector(REFERENCE_KEY);
-export type ReferenceDecoratorOpts<DTO, Relation> = Omit<ResolverRelationReference<DTO, Relation>, 'DTO'>;
+export type ReferenceDecoratorOpts<DTO, Relation> = Omit<ResolverRelationReference<DTO, Relation>, 'DTO' | 'keys'>;
 export type ReferenceTypeFunc<Relation> = () => Class<Relation>;
 
 interface ReferenceDescriptor<DTO, Reference> {
   name: string;
   keys: ReferencesKeys<DTO, Reference>;
   relationTypeFunc: () => Class<Reference>;
-  relationOpts?: Omit<ResolverRelationReference<DTO, Reference>, 'DTO'>;
+  relationOpts?: Omit<ResolverRelationReference<DTO, Reference>, 'DTO' | 'keys'>;
 }
 
 function getReferenceDescriptors<DTO>(DTOClass: Class<DTO>): ReferenceDescriptor<DTO, unknown>[] {

diff --git a/packages/query-graphql/src/resolvers/relations/references-relation.resolver.ts b/packages/query-graphql/src/resolvers/relations/references-relation.resolver.ts
@@ -16,6 +16,10 @@ const pluckFields = <DTO, Relation>(dto: DTO, fieldMap: ReferencesKeys<DTO, Rela
   return partial as Partial<Relation>;
 };
 
+const allFieldsAreNull = <Relation>(fields: Partial<Relation>): boolean => {
+  return Object.entries(fields).reduce<boolean>((previousNull, [, value]) => previousNull && value === null, true);
+};
+
 const ReferencesMixin = <DTO, Relation>(DTOClass: Class<DTO>, reference: ResolverRelationReference<DTO, Relation>) => <
   B extends Class<ServiceResolver<DTO, QueryService<DTO, unknown, unknown>>>
 >(
@@ -33,9 +37,15 @@ const ReferencesMixin = <DTO, Relation>(DTOClass: Class<DTO>, reference: Resolve
       { nullable: reference.nullable, complexity: reference.complexity },
       commonResolverOpts,
     )
-    [`${baseNameLower}Reference`](@Parent() dto: DTO): RepresentationType {
+    [`${baseNameLower}Reference`](@Parent() dto: DTO): RepresentationType | null {
+      const fields = pluckFields<DTO, Relation>(dto, reference.keys);
+
+      if (allFieldsAreNull(fields)) {
+        return null;
+      }
+
       // eslint-disable-next-line @typescript-eslint/naming-convention
-      return { __typename: baseName, ...pluckFields<DTO, Relation>(dto, reference.keys) };
+      return { __typename: baseName, ...fields };
     }
   }
   return ReadOneMixin;