GraphQL Dataloaders for NestJS

Description

Quick and easy GraphQL dataloaders for NestJS.

Installation

$ npm install @tracworx/nestjs-dataloader

Usage

Import the DataloaderModule in your root module.

import { Module } from '@nestjs/common';
import { DataloaderModule } from '@tracworx/nestjs-dataloader';
import { ItemResolver } from './item.resolver';
import { ItemLoader } from './item.loader';

@Module({
  imports: [DataloaderModule],
  providers: [ItemResolver, ItemLoader],
})
export class AppModule {}

Decorate dataloader factory classes with @DataloaderProvider() to automatically provide them to the GraphQL context object for each request.

import DataLoader from 'dataloader';
import { DataloaderProvider } from '@tracworx/nestjs-dataloader';

@DataloaderProvider()
class ItemLoader {
  createDataloader(ctx: GqlExecutionContext) {
    // Fetch request-scoped context data if needed
    const user = ctx.getContext().req.user;
    // Replace this with your actual dataloader implementation
    return new DataLoader<string, Item>(async (ids) => getItemsWithIds(user, ids));
  }
}

Use @Loader(...) to inject a dataloader instance into your resolver methods.

import DataLoader from 'dataloader';
import { Loader } from '@tracworx/nestjs-dataloader';
import { ItemLoader } from './item.loader';

@Resolver()
class ItemResolver {
  @Query(() => Item, { name: 'item' })
  getItem(@Args('id') id: string, @Loader(ItemLoader) itemLoader) {
    return itemLoader.load(id);
  }
}

And that's it. Happy coding!

Development

# build
$ npm run build

# format with prettier
$ npm run format

# lint with eslint
$ npm run lint

Test

# unit tests
$ npm run test

# e2e tests
$ npm run test:e2e

# test coverage
$ npm run test:cov

Stay in touch

• Author - Eoin O'Brien
• Website - https://tracworx.ai
• Twitter - @realEoinOBrien

License

@tracworx/nestjs-dataloader is MIT licensed.