How to Add GraphQL to Node.js: A Complete Guide

One of the most popular approaches to control APIs is using GraphQL. It has rapidly become one of the favourites because it gives a more powerful and adaptable alternative to REST. With this, developers can selectively request data, which increases flexibility as well as speed. 

You can follow this guide on including GraphQL in your Node.js app with Express.js. Whether you are working on a little project or expanding for more extensive uses, this guide will get you started.

What is GraphQL & Why Should You Use It?

GraphQL is an API query language. It also works as a runtime that can execute these queries with your information. GraphQL enables customers, unlike conventional REST APIs, to precisely query the data they need, therefore minimizing under-fetching and over-fetching of information.

Improving performance is made possible by better efficiency of client-server communication. With its great versatility, GraphQL makes it possible to grow and scale your API free of any versioning. 

Furthermore, via subscriptions, it supports real-time data updates. Many choose GraphQL to create contemporary, responsive, and scalable programs because of its declarative syntax and strong developer tools.

How to Add GraphQL to Node.js using Express to Create a GraphQL API

Implementing GraphQL in Node.js with Express assistance enables you to build a robust as well as a versatile API. Below are the steps that will help you build a GraphQL API.Ensure that Node.js is updated before commencing. This will provide for an uninterrupted run without any issues. In case it is not running smoothly, uninstall Node.js and then install it again. This will also provide for an uninterrupted run.

Step 1: Initialize the Node.js Project

The first step is to create a new folder and then initialize a Node.js project:

1. Create a new folder:
  ```bash
  mkdir graphql-express-api
  cd graphql-express-api
  ```

2. Initialize a new Node.js project:
  ```bash
  npm init -y
  ```

Step 2: Install Required Dependencies

Now, install the required libraries for Express, GraphQL, and the Express-GraphQL middleware:

Install the necessary libraries:

```bash
npm install express express-graphql graphql
```

Step 3: Create the Entry Point File

First, create an index.js file. It will operate as the main entry point. Here is the basic setup needed for this step:

```js
const express = require('express');
const { graphqlHTTP } = require('express-graphql');
const { buildSchema } = require('graphql');

const app = express();

// GraphQL schema
const schema = buildSchema(`
  type Query {
    hello: String
  }
`);

// Root resolver
const root = {
  hello: () => {
    return 'Hello world!';
  },
};

// GraphQL endpoint
app.use('/graphql', graphqlHTTP({
  schema: schema,
  rootValue: root,
  graphiql: true,
}));

app.listen(4000, () => console.log('Server running at http://localhost:4000/graphql'));

Step 4: Run the Server

Now, run the server by using the command:

node index.js

```bash
node index.js
```

Navigate to the location mentioned below

http://localhost:4000/graphql

Now you can check the GraphQL query with:

```graphql
{
  hello
}
```

Step 5: Expand the Schema

In order to make your API more useful, expand the schema with additional fields. For example, you can add a new greet query:

```js
const schema = buildSchema(`
  type Query {
    hello: String
    greet(name: String!): String
  }
`);

const root = {
  hello: () => 'Hello world!',
  greet: ({ name }) => `Hello, ${name}!`,
};
```

Test query:
```graphql
{
  greet(name: "John")
}
```

Step 6: Organize Codebase (Optional)

For bigger applications, it’s wise to systematize your code. Segregate the resolvers, schema, as well as other logic into various files:

• schema.js
  
• resolvers.js
  
• index.js
  

These steps are just a basic intro to adding GraphQL to Node.js. But you can do more with this. To make the most out of these technologies, it is always recommendable to hire Node.js developers from a trustworthy partner such as Soft Suave.