[Startup MVP recipes #4] GraphQL and a foo resolver

In this chapter we will add GraphQL module and set up an Apollo Studio playground to test a basic “Foo” resolver.

Official doc is also recommended:

https://docs.nestjs.com/graphql/quick-start

https://docs.nestjs.com/graphql/resolvers

Install NPM packages

npm i @nestjs/graphql @nestjs/apollo graphql apollo-server-express apollo-server-core

Add GraphQL Module to App Module (we are using code first approach)

// app.module.ts
import { join } from 'path';

import { ApolloDriver, ApolloDriverConfig } from '@nestjs/apollo';

import { GraphQLModule } from '@nestjs/graphql';

import { ApolloServerPluginLandingPageLocalDefault } from 'apollo-server-core';

GraphQLModule.forRoot<ApolloDriverConfig>({
  driver: ApolloDriver,
  debug: true,
  autoSchemaFile: join(process.cwd(), 'src/schema.gql'),
  sortSchema: true,
  playground: false,
  plugins: [ApolloServerPluginLandingPageLocalDefault()],
}),

Create a basic FooResolver to get started:

// app.resolver.ts

/* eslint-disable class-methods-use-this */
import { Query, Resolver } from '@nestjs/graphql';

@Resolver()
export default class FooResolver {
  @Query(() => String)
  sayHello() {
    return 'Hello World!';
  }
}

This simply provides a GQL query that returns Hello World!

Add the resolver to App Module:

// app.module.ts

import FooResolver from './app.resolver';

//..
providers: [FooResolver],

Then we can test the GQL query in local Apollo Studio: http://localhost:3000/graphql