fix(scalars): fix converting object scalars to instance

CHANGELOG.md

@@ -9,6 +9,8 @@
 ### Features
 - add support for creating and attaching middlewares, guards and interceptors to fields and resolvers
 - **Breaking Change**: remove deprecated decorators with `GraphQL` prefix and `{ array: true }` type option
+### Fixes
+- fix bug when converting object scalars to target class instance (#65)
 
 ## v0.10.0
 ### Features

src/helpers/types.ts

@@ -58,7 +58,11 @@ export function convertToType(Target: any, data?: object): object | undefined {
   if (data == null) {
     return;
   }
-  // skip simple types
+  // skip converting scalars (object scalar mostly)
+  if (Target instanceof GraphQLScalarType) {
+    return data;
+  }
+  // skip converting simple types
   if (simpleTypes.includes(data.constructor)) {
     return data;
   }

tests/functional/scalars.ts

@@ -24,7 +24,7 @@ import {
   GraphQLTimestamp,
 } from "../../src";
 import { getSchemaInfo } from "../helpers/getSchemaInfo";
-import { CustomScalar, CustomType } from "../helpers/customScalar";
+import { CustomScalar, CustomType, ObjectScalar } from "../helpers/customScalar";
 import { getSampleObjectFieldType } from "../helpers/getSampleObjectFieldType";
 import { MetadataStorage } from "../../src/metadata/metadata-storage";
 
@@ -103,6 +103,15 @@ describe("Scalars", () => {
         return true;
       }
 
+      @Query(returns => Boolean)
+      objectArgScalar(
+        @Arg("scalar", type => ObjectScalar)
+        scalar: any,
+      ): any {
+        argScalar = scalar;
+        return true;
+      }
+
       @Query(returns => Date)
       returnDate(): any {
         return new Date();
@@ -237,6 +246,15 @@ describe("Scalars", () => {
 
       expect(argScalar!).toEqual("TypeGraphQL parseLiteral");
     });
+
+    it("should properly parse scalar object", async () => {
+      const query = `query {
+        objectArgScalar(scalar: "test")
+      }`;
+      await graphql(schema, query);
+
+      expect(argScalar!).toEqual({ value: "TypeGraphQL parseLiteral" });
+    });
   });
 
   describe("Bulit-in scalars", () => {

tests/helpers/customScalar.ts

@@ -7,3 +7,14 @@ export const CustomScalar = new GraphQLScalarType({
   serialize: () => "TypeGraphQL serialize",
 });
 export class CustomType {}
+
+export const ObjectScalar = new GraphQLScalarType({
+  name: "ObjectScalar",
+  parseLiteral: () => ({
+    value: "TypeGraphQL parseLiteral",
+  }),
+  parseValue: () => ({
+    value: "TypeGraphQL parseValue",
+  }),
+  serialize: obj => obj.value,
+});