Setting up a Javascript GraphQL server

27 Sep 2023

GraphQL

GraphQL is a powerful query language that allows developers to define the structure of the data they need from an API. In this tutorial, we will walk through the process of setting up a JavaScript GraphQL server.

Prerequisites

To follow along with this tutorial, you will need the following:

Node.js installed on your machine
Basic knowledge of JavaScript and Node.js

Step 1: Initialize a Node.js Project

First, let’s create a new directory for our project and navigate into it using the command line. Then, run the following command to initialize a new Node.js project:

npm init -y

This will create a package.json file in the project directory.

Step 2: Install Required Dependencies

Next, we need to install the necessary dependencies for our GraphQL server. Run the following command to install express and graphql:

npm install express graphql

Step 3: Create a GraphQL Schema

Now, let’s create a file called schema.js to define our GraphQL schema. In this file, we will define the structure and types of our data.

const { GraphQLObjectType, GraphQLSchema, GraphQLString } = require('graphql');

const UserType = new GraphQLObjectType({
  name: 'User',
  fields: {
    id: { type: GraphQLString },
    name: { type: GraphQLString },
    email: { type: GraphQLString },
  },
});

const QueryType = new GraphQLObjectType({
  name: 'Query',
  fields: {
    user: {
      type: UserType,
      resolve: () => {
        // Resolve logic to fetch user data from the database
      },
    },
  },
});

const schema = new GraphQLSchema({
  query: QueryType,
});

module.exports = schema;

In this example, we define a UserType with id, name, and email fields. We also define a QueryType with a user field that resolves to a UserType object.

Step 4: Create an Express Server

Next, let’s create an Express server to handle HTTP requests and connect it to our GraphQL schema.

Create a file called server.js and add the following code:

const express = require('express');
const { graphqlHTTP } = require('express-graphql');
const schema = require('./schema');

const app = express();

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

app.listen(3000, () => {
  console.log('Server running on port 3000');
});

In this code, we import express and the graphqlHTTP middleware from the express-graphql package. We also import our schema from the ./schema file.

We then create an instance of the express server, specify a route for handling GraphQL requests (/graphql), and pass our schema to the graphqlHTTP middleware. We set graphiql to true to enable the GraphiQL interface for testing our GraphQL API.

Finally, we start the server on port 3000 and log a message to the console.

Step 5: Start the Server

To start the GraphQL server, run the following command in the terminal:

node server.js

You should see the message “Server running on port 3000” logged to the console, indicating that the server is running successfully.

Conclusion

In this tutorial, we have learned how to set up a JavaScript GraphQL server using Node.js, Express, and the graphql package. Now you can start building your GraphQL APIs and enjoy the flexibility and power it offers.

#javascript #GraphQL