add endpoint.

src/cats/cats.graphql

@@ -1,6 +1,7 @@
 type Query {
   cats: [Cat]
   cat(id: ID!): Cat
+  catByIds(ids: [ID!]): [Cat]
 }
 
 type Mutation {

src/cats/cats.resolver.ts

@@ -1,4 +1,4 @@
-import { ParseIntPipe, UseGuards } from '@nestjs/common';
+import { ParseArrayPipe, ParseIntPipe, UseGuards } from '@nestjs/common';
 import { Args, Mutation, Query, Resolver, Subscription } from '@nestjs/graphql';
 import { PubSub } from 'graphql-subscriptions';
 import { Cat } from '../graphql.schema';
@@ -26,6 +26,14 @@ export class CatsResolver {
     return this.catsService.findOneById(id);
   }
 
+  @Query('catByIds')
+  async findByIds(
+    @Args('ids', new ParseArrayPipe({ items: Number, separator: ',' }))
+    ids: number[],
+  ): Promise<Cat[]> {
+    return this.catsService.findByIds(ids);
+  }
+
   @Mutation('createCat')
   async create(@Args('createCatInput') args: CreateCatDto): Promise<Cat> {
     const createdCat = await this.catsService.create(args);

src/cats/cats.service.ts

@@ -24,4 +24,8 @@ export class CatsService {
   findOneById(id: number): Cat {
     return this.cats.find(cat => cat.id === id);
   }
+
+  findByIds(ids: number[]): Cat[] {
+    return ids.map(id => this.cats.find(cat => cat.id === id))
+  }
 }

src/graphql.schema.ts

@@ -1,39 +1,45 @@
-/** ------------------------------------------------------
+
+/*
+ * -------------------------------------------------------
  * THIS FILE WAS AUTOMATICALLY GENERATED (DO NOT MODIFY)
  * -------------------------------------------------------
  */
 
 /* tslint:disable */
 /* eslint-disable */
 export class CreateCatInput {
-  name?: string;
-  age?: number;
+    name?: Nullable<string>;
+    age?: Nullable<number>;
 }
 
 export abstract class IQuery {
-  abstract cats(): Cat[] | Promise<Cat[]>;
+    abstract cats(): Nullable<Nullable<Cat>[]> | Promise<Nullable<Nullable<Cat>[]>>;
 
-  abstract cat(id: string): Cat | Promise<Cat>;
+    abstract cat(id: string): Nullable<Cat> | Promise<Nullable<Cat>>;
+
+    abstract catByIds(ids?: Nullable<string[]>): Nullable<Nullable<Cat>[]> | Promise<Nullable<Nullable<Cat>[]>>;
 }
 
 export abstract class IMutation {
-  abstract createCat(createCatInput?: CreateCatInput): Cat | Promise<Cat>;
+    abstract createCat(createCatInput?: Nullable<CreateCatInput>): Nullable<Cat> | Promise<Nullable<Cat>>;
 }
 
 export abstract class ISubscription {
-  abstract catCreated(): Cat | Promise<Cat>;
+    abstract catCreated(): Nullable<Cat> | Promise<Nullable<Cat>>;
 }
 
 export class Owner {
-  id: number;
-  name: string;
-  age?: number;
-  cats?: Cat[];
+    id: number;
+    name: string;
+    age?: Nullable<number>;
+    cats?: Nullable<Cat[]>;
 }
 
 export class Cat {
-  id?: number;
-  name?: string;
-  age?: number;
-  owner?: Owner;
+    id?: Nullable<number>;
+    name?: Nullable<string>;
+    age?: Nullable<number>;
+    owner?: Nullable<Owner>;
 }
+
+type Nullable<T> = T | null;