Fed v1 - @external and extends (#23)

src/index.ts

@@ -17,6 +17,7 @@ import entityAndNoEntity from "./test-cases/entity-and-no-entity";
 import nonResolvableInterfaceObject from "./test-cases/non-resolvable-interface-object";
 import interfaceObjectWithRequires from "./test-cases/interface-object-with-requires";
 import requiresInterface from "./test-cases/requires-interface";
+import fed1ExternalExtends from "./test-cases/fed1-external-extends";
 
 const testCases = [
   unionIntersectionTestCase,
@@ -37,6 +38,7 @@ const testCases = [
   nonResolvableInterfaceObject,
   interfaceObjectWithRequires,
   requiresInterface,
+  fed1ExternalExtends,
 ];
 
 function routerFetch(

src/test-cases/fed1-external-extends/a.subgraph.ts

@@ -0,0 +1,43 @@
+import { createSubgraph } from "../../subgraph";
+import { users } from "./data";
+
+export default createSubgraph("a", {
+  typeDefs: /* GraphQL */ `
+    type Query {
+      randomUser: User
+    }
+
+    extend type User @key(fields: "id") {
+      id: ID! @external
+    }
+
+    extend type User {
+      name: String! @external
+    }
+  `,
+  resolvers: {
+    Query: {
+      randomUser() {
+        return {
+          id: users[0].id,
+        };
+      },
+    },
+    User: {
+      __resolveReference(key: { id: string }) {
+        const user = users.find((u) => u.id === key.id);
+
+        if (!user) {
+          return null;
+        }
+
+        return {
+          id: user.id,
+        };
+      },
+      name() {
+        return "never";
+      },
+    },
+  },
+});

src/test-cases/fed1-external-extends/b.subgraph.ts

@@ -0,0 +1,48 @@
+import { createSubgraph } from "../../subgraph";
+import { users } from "./data";
+
+export default createSubgraph("b", {
+  typeDefs: /* GraphQL */ `
+    type Query {
+      userById(id: ID): User
+    }
+
+    type User @key(fields: "id") {
+      id: ID!
+      name: String!
+      nickname: String
+    }
+  `,
+  resolvers: {
+    Query: {
+      userById: (_: {}, { id }: { id: string }) => {
+        const user = users.find((u) => u.id === id);
+
+        if (!user) {
+          return null;
+        }
+
+        return {
+          id: user.id,
+          name: user.name,
+          nickname: user.nickname,
+        };
+      },
+    },
+    User: {
+      __resolveReference: (key: { id: string }) => {
+        const user = users.find((u) => u.id === key.id);
+
+        if (!user) {
+          return null;
+        }
+
+        return {
+          id: user.id,
+          name: user.name,
+          nickname: user.nickname,
+        };
+      },
+    },
+  },
+});

src/test-cases/fed1-external-extends/data.ts

@@ -0,0 +1,12 @@
+export const users = [
+  {
+    id: "u1",
+    name: "u1-name",
+    nickname: "u1-nickname",
+  },
+  {
+    id: "u2",
+    name: "u2-name",
+    nickname: "u2-nickname",
+  },
+];

src/test-cases/fed1-external-extends/index.ts

@@ -0,0 +1,6 @@
+import { serve } from "../../supergraph";
+import a from "./a.subgraph";
+import b from "./b.subgraph";
+import test from "./test";
+
+export default serve("fed1-external-extends", [a, b], test);

src/test-cases/fed1-external-extends/test.ts

@@ -0,0 +1,32 @@
+import { createTest } from "../../test";
+
+export default [
+  createTest(
+    /* GraphQL */ `
+      query {
+        randomUser {
+          id
+          name
+        }
+        userById(id: "u2") {
+          id
+          name
+          nickname
+        }
+      }
+    `,
+    {
+      data: {
+        randomUser: {
+          id: "u1",
+          name: "u1-name",
+        },
+        userById: {
+          id: "u2",
+          name: "u2-name",
+          nickname: "u2-nickname",
+        },
+      },
+    }
+  ),
+];