refactor(createProxyingResolver): finish new functionality

src/Interfaces.ts

@@ -126,14 +126,12 @@ export type Dispatcher = (context: any) => ApolloLink | Fetcher;
 export interface SubschemaConfig {
   schema: GraphQLSchema;
   rootValue?: Record<string, any>;
-  executor?: Delegator;
-  subscriber?: Delegator;
   link?: ApolloLink;
   fetcher?: Fetcher;
   dispatcher?: Dispatcher;
+  createProxyingResolver?: CreateProxyingResolverFn;
   transforms?: Array<Transform>;
   merge?: Record<string, MergedTypeConfig>;
-  createProxyingResolver?: CreateProxyingResolverFn;
 }
 
 export interface MergedTypeConfig {
@@ -596,12 +594,9 @@ export type DirectiveMapper = (
   schema: GraphQLSchema,
 ) => GraphQLDirective | null | undefined;
 
-export interface ICreateProxyingResolverOptions {
-  schema?: GraphQLSchema | SubschemaConfig;
-  transforms?: Array<Transform>;
-  operation?: Operation;
-}
-
 export type CreateProxyingResolverFn = (
-  options: ICreateProxyingResolverOptions,
+  schema: GraphQLSchema | SubschemaConfig,
+  transforms: Array<Transform>,
+  operation: Operation,
+  fieldName: string,
 ) => GraphQLFieldResolver<any, any>;

src/wrap/index.ts

@@ -1,6 +1,8 @@
 export { wrapSchema } from './wrapSchema';
 export { transformSchema } from './transformSchema';
 
+export { defaultCreateProxyingResolver } from './resolvers';
+
 export * from './transforms/index';
 
 export {

src/wrap/makeRemoteExecutableSchema.ts

@@ -8,9 +8,7 @@ import {
   DocumentNode,
 } from 'graphql';
 
-import { addResolversToSchema } from '../generate/index';
-import { Fetcher, Operation } from '../Interfaces';
-import { cloneSchema } from '../utils/index';
+import { Fetcher } from '../Interfaces';
 import { buildSchema } from '../polyfills/index';
 import { addTypenameToAbstract } from '../delegate/addTypenameToAbstract';
 import { checkResultAndHandleErrors } from '../delegate/checkResultAndHandleErrors';
@@ -19,7 +17,7 @@ import linkToFetcher, { execute } from '../stitch/linkToFetcher';
 import { observableToAsyncIterable } from '../stitch/observableToAsyncIterable';
 import mapAsyncIterator from '../stitch/mapAsyncIterator';
 
-import { stripResolvers, generateProxyingResolvers } from './resolvers';
+import { wrapSchema } from './wrapSchema';
 
 export type ResolverFn = (
   rootValue?: any,
@@ -56,27 +54,15 @@ export default function makeRemoteExecutableSchema({
       ? buildSchema(schemaOrTypeDefs, buildSchemaOptions)
       : schemaOrTypeDefs;
 
-  const createProxyingResolver = ({
-    operation,
-  }: {
-    operation: Operation;
-  }): GraphQLFieldResolver<any, any> => {
-    if (operation === 'query' || operation === 'mutation') {
-      return createResolver(finalFetcher);
-    }
-    return createSubscriptionResolver(link);
-  };
-
-  const resolvers = generateProxyingResolvers({
-    subschemaConfig: { schema: targetSchema, createProxyingResolver },
+  return wrapSchema({
+    schema: targetSchema,
+    createProxyingResolver: (_schema, _transforms, operation) => {
+      if (operation === 'query' || operation === 'mutation') {
+        return createResolver(finalFetcher);
+      }
+      return createSubscriptionResolver(link);
+    },
   });
-
-  const remoteSchema = cloneSchema(targetSchema);
-
-  stripResolvers(remoteSchema);
-  addResolversToSchema({ schema: remoteSchema, resolvers });
-
-  return remoteSchema;
 }
 
 export function defaultCreateRemoteResolver(

src/wrap/resolvers.ts

@@ -40,20 +40,29 @@ export function generateProxyingResolvers({
 
   const resolvers = {};
   Object.keys(operationTypes).forEach((operation: Operation) => {
+    const resolveField = operation === 'subscription' ? 'subscribe' : 'resolve';
+
     const rootType = operationTypes[operation];
     if (rootType != null) {
       const typeName = rootType.name;
       const fields = rootType.getFields();
+
       resolvers[typeName] = {};
       Object.keys(fields).forEach((fieldName) => {
-        const resolveField =
-          operation === 'subscription' ? 'subscribe' : 'resolve';
+        const proxyingResolver = createProxyingResolver(
+          subschemaConfig,
+          transforms,
+          operation,
+          fieldName,
+        );
+
+        const finalResolver = createPossiblyNestedProxyingResolver(
+          subschemaConfig,
+          proxyingResolver,
+        );
+
         resolvers[typeName][fieldName] = {
-          [resolveField]: createProxyingResolver({
-            schema: subschemaConfig,
-            transforms,
-            operation,
-          }),
+          [resolveField]: finalResolver,
         };
       });
     }
@@ -62,14 +71,11 @@ export function generateProxyingResolvers({
   return resolvers;
 }
 
-function defaultCreateProxyingResolver({
-  schema,
-  transforms,
-}: {
-  schema: SubschemaConfig;
-  transforms: Array<Transform>;
-}): GraphQLFieldResolver<any, any> {
-  return (parent, _args, context, info) => {
+function createPossiblyNestedProxyingResolver(
+  subschemaConfig: SubschemaConfig,
+  proxyingResolver: GraphQLFieldResolver<any, any>,
+): GraphQLFieldResolver<any, any> {
+  return (parent, args, context, info) => {
     if (parent != null) {
       const responseKey = getResponseKeyFromInfo(info);
       const errors = getErrors(parent, responseKey);
@@ -81,7 +87,7 @@ function defaultCreateProxyingResolver({
         // If there is a proxied result from this subschema, return it
         // This can happen even for a root field when the root type ia
         // also nested as a field within a different type.
-        if (schema === subschema) {
+        if (subschemaConfig === subschema) {
           return handleResult(
             parent[responseKey],
             errors,
@@ -93,13 +99,21 @@ function defaultCreateProxyingResolver({
       }
     }
 
-    return delegateToSchema({
+    return proxyingResolver(parent, args, context, info);
+  };
+}
+
+export function defaultCreateProxyingResolver(
+  schema: GraphQLSchema | SubschemaConfig,
+  transforms: Array<Transform>,
+): GraphQLFieldResolver<any, any> {
+  return (_parent, _args, context, info) =>
+    delegateToSchema({
       schema,
       context,
       info,
       transforms,
     });
-  };
 }
 
 export function stripResolvers(schema: GraphQLSchema): void {