Make batch delegate send key arrays to loadMany (#1865)

ardatan · Aug 2, 2020 · 7c55fbe · 7c55fbe
1 parent 66081f7
commit 7c55fbe
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Showing 2 changed files with 116 additions and 2 deletions.
diff --git a/packages/batch-delegate/src/batchDelegateToSchema.ts b/packages/batch-delegate/src/batchDelegateToSchema.ts
@@ -3,6 +3,12 @@ import { BatchDelegateOptions } from './types';
 import { getLoader } from './getLoader';
 
 export function batchDelegateToSchema(options: BatchDelegateOptions): any {
+  const key = options.key;
+  if (key == null) {
+    return null;
+  } else if (Array.isArray(key) && !key.length) {
+    return [];
+  }
   const loader = getLoader(options);
-  return loader.load(options.key);
+  return Array.isArray(key) ? loader.loadMany(key) : loader.load(key);
 }
diff --git a/packages/batch-delegate/tests/basic.example.test.ts b/packages/batch-delegate/tests/basic.example.test.ts
@@ -5,7 +5,7 @@ import { batchDelegateToSchema } from '@graphql-tools/batch-delegate';
 import { stitchSchemas } from '@graphql-tools/stitch';
 
 describe('batch delegation within basic stitching example', () => {
-  test('works', async () => {
+  test('works with single keys', async () => {
     let numCalls = 0;
 
     const chirpSchema = makeExecutableSchema({
@@ -91,4 +91,112 @@ describe('batch delegation within basic stitching example', () => {
     expect(result.errors).toBeUndefined();
     expect(result.data.trendingChirps[0].chirpedAtUser.email).not.toBe(null);
   });
+
+  test('works with key arrays', async () => {
+    let numCalls = 0;
+
+    const postsSchema = makeExecutableSchema({
+      typeDefs: `
+        type Post {
+          id: ID!
+          title: String
+        }
+
+        type Query {
+          posts(ids: [ID]!): [Post]!
+        }
+      `,
+      resolvers: {
+        Query: {
+          posts: (obj, args) => {
+            numCalls += 1;
+            return args.ids.map(id => ({ id, title: `Post ${id}` }));
+          }
+        }
+      }
+    });
+
+    const usersSchema = makeExecutableSchema({
+      typeDefs: `
+        type User {
+          id: ID!
+          postIds: [ID]!
+        }
+
+        type Query {
+          users(ids: [ID!]!): [User]!
+        }
+      `,
+      resolvers: {
+        Query: {
+          users: (obj, args) => {
+            return args.ids.map(id => {
+              return { id, postIds: [Number(id)+1, Number(id)+2] };
+            });
+          }
+        }
+      }
+    });
+
+    const linkTypeDefs = `
+      extend type User {
+        posts: [Post]!
+      }
+    `;
+
+    const stitchedSchema = stitchSchemas({
+      subschemas: [postsSchema, usersSchema],
+      typeDefs: linkTypeDefs,
+      resolvers: {
+        User: {
+          posts: {
+            selectionSet: `{ postIds }`,
+            resolve(user, _args, context, info) {
+              return batchDelegateToSchema({
+                schema: postsSchema,
+                operation: 'query',
+                fieldName: 'posts',
+                key: user.postIds,
+                context,
+                info,
+              });
+            },
+          },
+        },
+      },
+    });
+
+    const query = `
+      query {
+        users(ids: [1, 7]) {
+          id
+          posts {
+            id
+            title
+          }
+        }
+      }
+    `;
+
+    const result = await graphql(stitchedSchema, query);
+    expect(numCalls).toEqual(1);
+    expect(result.data).toEqual({
+      users: [
+        {
+          id: '1',
+          posts: [
+            { id: '2', title: 'Post 2' },
+            { id: '3', title: 'Post 3' }
+          ]
+        },
+        {
+          id: '7',
+          posts: [
+            { id: '8', title: 'Post 8' },
+            { id: '9', title: 'Post 9' }
+          ]
+        }
+      ]
+    });
+  });
 });