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How to Use GraphQL with Apollo Client: A Step-by-Step Guide

Want to use GraphQL with Apollo Client in your project? Apollo Client simplifies data fetching, caching, and state management for GraphQL-powered applications. In this guide, you’ll learn how to set up Apollo Client, execute queries and mutations, and optimize performance with real-world examples.

Why Apollo Client is the Best Choice for GraphQL

Apollo Client is a powerful state management library designed for GraphQL. Here’s why developers prefer it:

Declarative data fetching – Write queries directly in your components.
Smart caching – Reduces redundant API calls with a normalized cache.
Real-time updates – Supports GraphQL subscriptions for live data.
Optimistic UI – Instantly reflect changes before server confirmation.
Error handling – Built-in tools for graceful error management.

“Apollo Client turns GraphQL into a seamless experience, making data management intuitive and efficient.”

Setting Up Apollo Client

Step 1: Install Required Packages

Run this command to install Apollo Client and GraphQL:

npm install @apollo/client graphql

Step 2: Initialize Apollo Client

Configure the client with your GraphQL endpoint:

import { ApolloClient, InMemoryCache } from "@apollo/client";  
 
const client = new ApolloClient({  
  uri: "https://your-api.com/graphql",  
  cache: new InMemoryCache(),  
});

uri – Your GraphQL server URL.
cache – Uses InMemoryCache for efficient data storage.

Step 3: Wrap Your App with ApolloProvider

Make the client available globally:

import { ApolloProvider } from "@apollo/client";  
 
function App() {  
  return (  
    <ApolloProvider client={client}>  
      <YourApp />  
    </ApolloProvider>  
  );  
}

Fetching Data with GraphQL Queries

Basic Query Example

Use useQuery to fetch data:

import { gql, useQuery } from "@apollo/client";  
 
const GET_USERS = gql`  
  query GetUsers {  
    users {  
      id  
      name  
      email  
    }  
  }  
`;  
 
function UsersList() {  
  const { loading, error, data } = useQuery(GET_USERS);  
 
  if (loading) return <p>Loading...</p>;  
  if (error) return <p>Error: {error.message}</p>;  
 
  return (  
    <ul>  
      {data?.users?.map((user) => (  
        <li key={user.id}>{user.name}</li>  
      ))}  
    </ul>  
  );  
}

Dynamic Queries with Variables

Pass variables for dynamic data:

const GET_USER = gql`  
  query GetUser($id: ID!) {  
    user(id: $id) {  
      name  
      email  
    }  
  }  
`;  
 
function UserProfile({ userId }) {  
  const { loading, error, data } = useQuery(GET_USER, {  
    variables: { id: userId },  
  });  
  // Handle loading/error states  
}

Modifying Data with Mutations

Basic Mutation Example

Use useMutation to update data:

const ADD_USER = gql`  
  mutation AddUser($name: String!, $email: String!) {  
    addUser(name: $name, email: $email) {  
      id  
      name  
    }  
  }  
`;  
 
function AddUserForm() {  
  const [addUser, { loading, error }] = useMutation(ADD_USER);  
 
  const handleSubmit = (name, email) => {  
    addUser({ variables: { name, email } });  
  };  
  // Form implementation  
}

Optimistic UI Updates

Improve responsiveness with optimistic responses:

addUser({  
  variables: { name, email },  
  optimisticResponse: {  
    __typename: "Mutation",  
    addUser: {  
      __typename: "User",  
      id: "temp-id",  
      name,  
      email,  
    },  
  },  
});

Advanced Features

Real-Time Data with Subscriptions

Use useSubscription for live updates:

const MESSAGES_SUBSCRIPTION = gql`  
  subscription OnMessageAdded {  
    messageAdded {  
      id  
      text  
    }  
  }  
`;  
 
function Chat() {  
  const { data } = useSubscription(MESSAGES_SUBSCRIPTION);  
  return <div>{data?.messageAdded?.text}</div>;  
}

Best Practices for Performance

Cache strategies – Use fetchPolicy to control caching (cache-first, network-only).
Error handling – Implement global error handling with ApolloLink.
Pagination – Use fetchMore for large datasets.
Fragments – Reuse query segments for cleaner code.

#GraphQL #ApolloClient #WebDevelopment #Frontend #StateManagement

How to use graphql with apollo client

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