@dessly/nestjs-dataloader

📦 Zero-config DataLoader integration for NestJS 11 + GraphQL Yoga

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Installation

1npm i @dessly/nestjs-dataloader

Quick Start

1. Connect the module

1// core.module.ts
2import { Module } from '@nestjs/common';
3import {
4  GraphQLModule,
5} from '@nestjs/graphql';
6import {
7  YogaFederationDriver,
8  YogaFederationDriverConfig,
9} from '@graphql-yoga/nestjs-federation';
10import { DataloaderModule, DATALOADER_ENVELOP_PLUGIN } from '@dessly/nestjs-dataloader';
11
12@Module({
13  imports: [
14    /** ① add the global module */
15    DataloaderModule,
16
17    /** ② connect GraphQL via forRootAsync
18        and get the Envelop plugin from DI  */
19    GraphQLModule.forRootAsync<YogaFederationDriverConfig>({
20      driver: YogaFederationDriver,
21      imports: [DataloaderModule],
22      inject: [DATALOADER_ENVELOP_PLUGIN],
23      useFactory: (dataloaderPlugin) => ({
24        driver: YogaFederationDriver,
25        autoSchemaFile: { federation: 2 },
26        context: ({ req }) => ({ req }),
27        plugins: [dataloaderPlugin],          // ← DataLoader-plugin
28      }),
29    }),
30  ],
31})
32export class CoreModule {}

2. Define DataLoader

1// author.loader.ts
2import DataLoader from 'dataloader';
3import { DataloaderProvider } from '@dessly/nestjs-dataloader';
4import { AuthorService } from './author.service';
5import { Author } from './author.entity';
6
7@DataloaderProvider()
8export class AuthorLoader {
9  constructor(private readonly svc: AuthorService) {}
10
11  /** helper: SELECT ... WHERE id IN (ids) and return in the correct order */
12  createDataloader(): DataLoader<number, Author | null> {
13    return new DataLoader(async (ids: readonly number[]) => {
14      const rows = await this.svc.findManyByIds(ids as number[]);
15      const map = new Map(rows.map((r) => [r.id, r]));
16      return ids.map((id) => map.get(id) ?? null);
17    });
18  }
19}

3. Use in resolver

1// book.resolver.ts
2import { ResolveField, Resolver, Parent } from '@nestjs/graphql';
3import { Loader } from '@dessly/nestjs-dataloader';
4import { AuthorLoader } from './author.loader';
5import DataLoader from 'dataloader';
6import { Book } from './book.entity';
7import { Author } from './author.entity';
8
9@Resolver(() => Book)
10export class BookResolver {
11  @ResolveField(() => Author, { name: 'author' })
12  author(
13    @Parent() book: Book,
14    @Loader(AuthorLoader) loader: DataLoader<number, Author | null>,
15  ) {
16    return loader.load(book.authorId);
17  }
18}