fix(extensions): support defining on field resolver level for fields

CHANGELOG.md

@@ -6,6 +6,8 @@
 - **Breaking Change**: `AuthChecker` type is now "function or class" - update to `AuthCheckerFn` if the function form is needed in the code
 - support class-based auth checker, which allows for dependency injection
 - allow defining directives for interface types and theirs fields, with inheritance for object types fields (#744)
+### Fixes
+- allow defining extension on field resolver level for fields also defined as a property of the class (#776)
 ### Others
 - **Breaking Change**: update `graphql-js` peer dependency to `^15.4.0`
 

src/schema/schema-generator.ts

@@ -343,6 +343,7 @@ export abstract class SchemaGenerator {
                   extensions: {
                     complexity: field.complexity,
                     ...field.extensions,
+                    ...fieldResolverMetadata?.extensions,
                   },
                 };
                 return fieldsMap;

tests/functional/extensions.ts

@@ -321,5 +321,44 @@ describe("Extensions", () => {
         expect(childObjectTypeParentField.extensions).toEqual({ parentField: true });
       });
     });
+
+    describe("Fields with field resolvers", () => {
+      beforeAll(async () => {
+        getMetadataStorage().clear();
+
+        @ObjectType()
+        class Child {
+          @Field()
+          @Extensions({ childField: true })
+          childField!: string;
+        }
+        @Resolver(of => Child)
+        class ChildResolver {
+          @Query()
+          sampleQuery(): Child {
+            return {} as Child;
+          }
+
+          @Extensions({ childFieldResolver: true })
+          @FieldResolver()
+          childField(): string {
+            return "childField";
+          }
+        }
+
+        schema = await buildSchema({
+          resolvers: [ChildResolver],
+        });
+      });
+
+      it("should merge field level with field resolver level extensions", () => {
+        const childObjectType = schema.getType("Child") as GraphQLObjectType;
+
+        expect(childObjectType.getFields().childField.extensions).toEqual({
+          childField: true,
+          childFieldResolver: true,
+        });
+      });
+    });
   });
 });