fix(args convertion): errors when converting gql objects

Author: MichalLytek

CHANGELOG.md

@@ -5,6 +5,7 @@
 - fix missing type args in schema when declared in field resolver
 - fix missing resolver function when defined as type field method
 - fix creating instances of root object when internal fields are Promises (switch from `plainToClass` to vanilla JS)
+- fix convertings field and resolvers args errors while converting gql objects (weird `prototype` stuffs)
 
 ### 0.1.1
 #### Features

src/resolvers/create.ts

@@ -5,6 +5,7 @@ import { IOCContainer } from "../utils/container";
 import { FieldResolverDefinition, ParamDefinition } from "../metadata/definition-interfaces";
 import { getParams } from "./helpers";
 import { BaseResolverDefinitions } from "../types/resolvers";
+import { convertToType } from "../types/convert";
 
 export function createResolver(
   resolverDefinition: BaseResolverDefinitions,
@@ -25,10 +26,7 @@ export function createFieldResolver(
 
   const targetType = fieldResolverDefintion.getParentType!();
   return (root, args, context, info) => {
-    // const targetData = { ...root }; // workaround for plainToClass bug
-    // const targetInstance: any = plainToClass(targetType as any, targetData);
-    const targetInstance: any = Object.assign({}, root);
-    Object.setPrototypeOf(targetInstance, targetType.prototype);
+    const targetInstance: any = convertToType(targetType, root);
 
     // method
     if (fieldResolverDefintion.handler) {

src/resolvers/helpers.ts

@@ -1,6 +1,7 @@
 import { plainToClass } from "class-transformer";
 
 import { ParamDefinition } from "../metadata/definition-interfaces";
+import { convertToType } from "../types/convert";
 
 export interface ResolverData {
   root: any;
@@ -15,9 +16,9 @@ export function getParams(
   return params.sort((a, b) => a.index - b.index).map(paramInfo => {
     switch (paramInfo.kind) {
       case "args":
-        return plainToClass(paramInfo.getType() as any, args);
+        return convertToType(paramInfo.getType(), args);
       case "arg":
-        return plainToClass(paramInfo.getType() as any, args[paramInfo.name]);
+        return convertToType(paramInfo.getType(), args[paramInfo.name]);
       case "context":
         return context;
       case "root":

src/types/convert.ts

@@ -0,0 +1,14 @@
+const simpleTypes: Function[] = [String, Boolean, Number, Date, Array, Promise];
+
+export function convertToType(target: any, data?: object): object|undefined {
+  // skip converting undefined and null
+  if (data == null) {
+    return;
+  }
+  // skip simple types
+  if (simpleTypes.includes(data.constructor)) {
+    return data;
+  }
+
+  return Object.assign(Object.create(target.prototype), data);
+}