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Node.js Backend Development Bootcamp · Lección

Creación de un servidor GraphQL con Apollo

Implemente una API GraphQL en Node.js mediante Apollo Server, conéctela a sus fuentes de datos y defina resolvers.

Creación de un servidor GraphQL con Apollo es una lección gratuita de Node.js Backend Development Bootcamp en CoddyKit. Esta es la lección 3 de 4. Puedes leer la lección completa abajo gratuitamente — luego la practicas en el navegador con un editor de código integrado y un tutor de IA 24/7. Forma parte de la ruta de aprendizaje de Node.js Backend Development Bootcamp, y tu progreso se sincroniza en la web y la app de CoddyKit. El curso de Node.js Backend Development Bootcamp incluye 4 lecciones en total.

Partes de esta lección aún no han sido traducidas y se muestran en inglés.

Meet Apollo Server

Welcome to building a GraphQL server! We'll use Apollo Server, a popular open-source library that helps you implement a production-ready GraphQL API in Node.js.

  • It's easy to set up.
  • It integrates with many Node.js frameworks like Express.
  • It provides powerful tools like GraphQL Playground for testing.

Apollo Server handles the heavy lifting, letting you focus on your data.

Creación de un servidor GraphQL con Apollo — ilustración 1

Project Setup for Apollo

Let's get started by setting up our project. Open your terminal and run these commands to create a new Node.js project and install the required libraries:

  • apollo-server: The core library for building our GraphQL server.
  • graphql: The JavaScript implementation of the GraphQL specification.

Here's how to do it:

mkdir my-graphql-api
cd my-graphql-api
npm init -y
npm install apollo-server graphql

Once installed, you're ready to write some code!

Schema & Resolvers: The Core

A GraphQL server has two main parts:

  • Schema (Type Definitions): This defines the shape of your data and the operations clients can perform (queries, mutations). Think of it as the contract between client and server.
  • Resolvers: These are functions that tell GraphQL how to fetch the data for each type and field defined in your schema. They are the "backend logic" for your API.

Together, they define your API's capabilities and how it interacts with your data.

Crafting Your GraphQL Schema

We define the schema using a special template literal tag called gql (from apollo-server). This allows us to write GraphQL Schema Definition Language (SDL).

The most important type is Query, which defines all the ways clients can read data from your API. Let's define a simple Query that returns a "hello" message.

const { gql } = require('apollo-server');

const typeDefs = gql`
  type Query {
    hello: String
  }
`;

console.log('Your schema is ready!');

Building Your Resolvers

Now that we have our schema, we need to tell GraphQL how to actually get the data for the hello field. This is where resolvers come in.

Resolvers are functions that match the fields in your schema. When a client queries hello, the corresponding resolver function will be executed.

const resolvers = {
  Query: {
    hello: () => 'Hello from your GraphQL API!',
  },
};

console.log('Resolvers are defined!');

Launching Your First Server

Let's put it all together! We'll combine the typeDefs and resolvers with ApolloServer to create a complete, runnable GraphQL server.

Create a file named index.js and add the following code. Then, run it with node index.js.

const { ApolloServer, gql } = require('apollo-server');

// 1. Define your schema (type definitions)
const typeDefs = gql`
  type Query {
    hello: String
  }
`;

// 2. Define your resolvers (how to fetch data)
const resolvers = {
  Query: {
    hello: () => 'Hello from your GraphQL API!',
  },
};

// 3. Create an Apollo Server instance
const server = new ApolloServer({ typeDefs, resolvers });

// 4. Start the server
server.listen({ port: 4000 }).then(({ url }) => {
  console.log(`🚀 Server ready at ${url}`);
  console.log('Try opening your browser to test it!');
});

Defining Custom Data Types

A simple "hello" isn't very exciting. Let's define a custom type, like Book, with its own fields. This shows how you structure more complex data.

Update your typeDefs to include the Book type and a books query that returns a list of them.

const { gql } = require('apollo-server');

const typeDefs = gql`
  type Book {
    title: String
    author: String
  }

  type Query {
    hello: String
    books: [Book]
  }
`;

console.log('Schema updated with Book type!');

Resolving Custom Types

To make the books query work, we need to update our resolvers. For now, we'll use an in-memory array of objects to simulate a database. In real applications, resolvers connect to databases or other APIs.

Let's update the resolvers to provide data for our books query.

const books = [
  {
    title: 'The Great Gatsby',
    author: 'F. Scott Fitzgerald',
  },
  {
    title: 'To Kill a Mockingbird',
    author: 'Harper Lee',
  },
];

const resolvers = {
  Query: {
    hello: () => 'Hello from your GraphQL API!',
    books: () => books,
  },
};

console.log('Resolvers updated for books!');

Full API with Books

Here's the complete index.js file with our new Book type and its resolver. Run this with node index.js.

Once running, open the URL in your browser (e.g., http://localhost:4000). You'll see the GraphQL Playground, where you can test queries like:

query {
  books {
    title
    author
  }
}

const { ApolloServer, gql } = require('apollo-server');

const typeDefs = gql`
  type Book {
    title: String
    author: String
  }

  type Query {
    hello: String
    books: [Book]
  }
`;

const books = [
  {
    title: 'The Great Gatsby',
    author: 'F. Scott Fitzgerald',
  },
  {
    title: 'To Kill a Mockingbird',
    author: 'Harper Lee',
  },
];

const resolvers = {
  Query: {
    hello: () => 'Hello from your GraphQL API!',
    books: () => books,
  },
};

const server = new ApolloServer({ typeDefs, resolvers });

server.listen({ port: 4000 }).then(({ url }) => {
  console.log(`🚀 Server ready at ${url}`);
  console.log('Explore your API in GraphQL Playground!');
});

Schema vs. Resolvers Check

You've learned about the two fundamental parts of a GraphQL server: the schema (type definitions) and the resolvers.

Which of the following best describes the primary role of GraphQL Resolvers in an Apollo Server?

Apollo Server: Quick Recap

Great job! You've successfully built your first GraphQL server with Apollo Server.

  • We installed apollo-server and graphql.
  • We defined our API's structure using Type Definitions (typeDefs) written in GraphQL SDL.
  • We implemented Resolvers to specify how to fetch data for the fields in our schema, using mock data.
  • We launched our server using ApolloServer and explored it with GraphQL Playground.

This is the foundation for building powerful and flexible GraphQL APIs. Next, you can explore mutations, arguments, and connecting to real databases!

Preguntas frecuentes

¿La lección «Creación de un servidor GraphQL con Apollo» es gratis?

Sí — el texto completo de «Creación de un servidor GraphQL con Apollo» es gratis para leer aquí en la web. Para practicarla de forma interactiva (editor de código integrado y tutor de IA 24/7) y desbloquear el resto del curso de Node.js Backend Development Bootcamp, actualiza a CoddyKit PRO. El curso de Node.js Backend Development Bootcamp incluye 4 lecciones en total.

¿Qué aprenderé en «Creación de un servidor GraphQL con Apollo»?

Implemente una API GraphQL en Node.js mediante Apollo Server, conéctela a sus fuentes de datos y defina resolvers. Practicas Node.js Backend Development Bootcamp con código real que ejecutas directamente en el navegador, y un tutor de IA 24/7 responde tus preguntas mientras trabajas en la lección.

¿Necesito experiencia previa para empezar Node.js Backend Development Bootcamp?

No se requiere experiencia previa. Node.js Backend Development Bootcamp en CoddyKit está estructurado para principiantes hasta estudiantes avanzados, así que puedes empezar aquí o desde el inicio y avanzar a tu ritmo. Esta es la lección 3 de 4.

¿Cuánto tiempo toma la lección «Creación de un servidor GraphQL con Apollo»?

La mayoría de las lecciones de CoddyKit toman alrededor de 5–10 minutos. Cada una es compacta e interactiva, así que avanzas constantemente y retomas exactamente por donde dejaste en la web y la app.

¿Puedo escribir y ejecutar código en esta lección de Node.js Backend Development Bootcamp?

Sí. Cada lección de Node.js Backend Development Bootcamp incluye un editor de código integrado, así que escribes y ejecutas código real directamente en tu navegador y obtienes retroalimentación instantánea de IA — sin configuración local necesaria.

Todas las lecciones de este curso

  1. Introducción al serverless con Node.js
  2. Principios de diseño de API GraphQL
  3. Creación de un servidor GraphQL con Apollo
  4. Suscripciones de GraphQL para datos en tiempo real
← Volver a Node.js Backend Development Bootcamp