GraphQL Cheatsheet for fast paced website developers and product managers

As architects navigate the complexities of building enterprise-level applications with GraphQL, a structured codebase becomes pivotal. The following cheatsheet offers a progressive approach, from basic to expert levels, demonstrating how to organize code for GraphQL applications across popular frameworks like Vue.js, React, Node.js, and Angular.

Basic Level: This level introduces fundamental project structures, promoting clarity and separation of concerns. It’s ideal for smaller projects or those starting with GraphQL.

Intermediate Level: As projects grow, this level introduces more sophisticated organization, emphasizing scalability and maintainability. It incorporates folder structures for modules, services, and utilities.

Advanced Level: Suitable for larger enterprises, the advanced level optimizes for complexity. It introduces additional layers, such as context providers, middleware, and configuration files, ensuring a robust foundation for extensive applications.

Expert Level: Tailored for architects dealing with highly intricate projects, this level refines and extends previous structures. It incorporates advanced features and optimizations, offering a blueprint for architecting sophisticated GraphQL applications at an enterprise scale.

Whether you’re embarking on a new GraphQL project or refining an existing one, these cheatsheets serve as valuable guides for structuring codebases that align with enterprise-level architectural principles.

1. Installation:

Node.js: Install the required packages using npm.

npm install graphql express express-graphql

2. Basic Query Example:

graphqlCopy code

query {
  hello
}

3. Configuration Example — Vue.js:

Install Apollo Client for Vue.js.

npm install apollo-boost vue-apollo graphql

Use Apollo Client in your Vue.js application.

// main.js
import Vue from 'vue';
import ApolloClient from 'apollo-boost';
import VueApollo from 'vue-apollo';

Vue.use(VueApollo);
const apolloClient = new ApolloClient({
   uri: 'your-graphql-endpoint',
});
const apolloProvider = new VueApollo({
   defaultClient: apolloClient,
});
new Vue({
   // ...
   apolloProvider,
}).$mount('#app');

4. Configuration Example — React.js:

Install Apollo Client for React.js.

npm install @apollo/client graphql

Use Apollo Client in your React.js application.

// App.js
import React from 'react';
import { ApolloProvider, ApolloClient, InMemoryCache } from '@apollo/client';
const client = new ApolloClient({
   uri: 'your-graphql-endpoint',
   cache: new InMemoryCache(),
});
function App() {
   return (
     <ApolloProvider client={client}>
       {/* Your React components */}
     </ApolloProvider>
   );
}
export default App;

5. Configuration Example — Angular:

Install Apollo Client for Angular.

ng add apollo-angular

Use Apollo Client in your Angular application.

// app.module.ts
import { NgModule } from '@angular/core';
import { ApolloModule, Apollo } from 'apollo-angular';
import { HttpLinkModule, HttpLink } from 'apollo-angular-link-http';
import { InMemoryCache } from 'apollo-cache-inmemory';
@NgModule({
   imports: [
     ApolloModule,
     HttpLinkModule,
   ],
})
export class GraphQLModule {
   constructor(apollo: Apollo, httpLink: HttpLink) {
     apollo.create({
       link: httpLink.create({ uri: 'your-graphql-endpoint' }),
       cache: new InMemoryCache(),
     });
   }
}

This basic level GraphQL cheatsheet covers installation and configuration examples for Vue.js, React.js, and Angular.

Intermediate Level GraphQL Cheatsheet:

1. Advanced Query Example:

query {
  user(id: 1) {
    name
    email
    posts {
      title
      comments {
        text
      }
    }
  }
}

2. Mutation Example:

mutation {
  createUser(input: { name: "John", email: "john@example.com" }) {
    id
    name
    email
  }
}

3. Fragments:

graphqlCopy code

fragment UserData on User {
  id
  name
  email
}

query {
  user(id: 1) {
    ...UserData
    posts {
      title
    }
  }
}

4. Configuration Example — Angular:

Implement Angular services for GraphQL operations.

// graphql.service.ts
import { Injectable } from '@angular/core';
import { Apollo } from 'apollo-angular';
import gql from 'graphql-tag';

@Injectable({
   providedIn: 'root',
})

export class GraphQLService {
   constructor(private apollo: Apollo) {}

   getUser(id: number) {
     return this.apollo.query({
       query: gql`
         query GetUser($id: Int!) {
           user(id: $id) {
             id
             name
             email
           }
         }
       `,
       variables: { id },
     });
   }
}

This intermediate level GraphQL cheatsheet introduces advanced queries, mutations, and the use of fragments. It also includes state management integration for Vue.js, React.js, and Angular.

Advanced Level GraphQL Cheatsheet:

1. Subscriptions:

Real-time updates with GraphQL subscriptions.

subscription {
   newPost {
     title
     content
   }
}

2. Apollo Client Caching:

Use Apollo Client cache for efficient state management.

// In your Apollo Client setup
new ApolloClient({
   cache: new InMemoryCache(),
   link: YOUR_LINK,
});

3. Dynamic Queries:

Construct queries dynamically based on user input.

const GET_USER = gql`
   query GetUser($id: Int!) {
     user(id: $id) {
       id
       name
       email
     }
   }
`;
const { loading, error, data } = useQuery(GET_USER, {
   variables: { id: userId },
});

4. Configuration Example — Node.js (Apollo Server):

Implement Apollo Server with Express.

const { ApolloServer, gql } = require('apollo-server-express');
const express = require('express');
const typeDefs = gql`
   type Query {
     hello: String
   }
`;
const resolvers = {
   Query: {
     hello: () => 'Hello, GraphQL!',
   },
};
const server = new ApolloServer({ typeDefs, resolvers });
const app = express(); 
server.applyMiddleware({ app });
app.listen({ port: 4000 }, () =>
   console.log(`Server ready at http://localhost:4000${server.graphqlPath}`)
);

5. GraphQL Directives:

Utilize directives for conditional queries.

query {
   user(id: 1) {
     name
     email
     posts @include(if: $withPosts) {
       title
     }
   }
}

6. Configuration Example — Bootstrap:

Implement Bootstrap styles for GraphQL Playground.

// In your HTML file
<link
   rel="stylesheet"
   href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
   integrity="YOUR_INTEGRITY"
   crossorigin="anonymous" />

This advanced-level GraphQL cheatsheet introduces real-time subscriptions, advanced caching, dynamic queries, and directives. Additionally, it provides a configuration example for Node.js (Apollo Server) and Bootstrap styling for GraphQL Playground.

Expert Level GraphQL Cheatsheet:

1. Federation:

Implement GraphQL federation for microservices.

// In your Apollo Server setup
const { ApolloGateway } = require('@apollo/gateway');
const gateway = new ApolloGateway({
   serviceList: [
     { name: 'accounts', url: 'http://localhost:4001' },
     { name: 'inventory', url: 'http://localhost:4002' },
     // Add more services
   ],
});
const server = new ApolloServer({ gateway, subscriptions: false });

2. Custom Scalars:

Create and use custom scalars for specific data types.

scalar DateTime  type Event {
   name: String
   date: DateTime
}

3. Schema Stitching:

Combine multiple schemas into a single, cohesive schema.

// In your Apollo Server setup
const { ApolloServer } = require('apollo-server');
const { stitchSchemas } = require('@graphql-tools/stitch');
const gatewaySchema = await stitchSchemas({
   subschemas: [accountsSchema, inventorySchema],
});
const server = new ApolloServer({ schema: gatewaySchema });

4. Configuration Example — Vue.js:

Integrate Apollo Client with Vue.js.

// In your Vue.js component
import { ApolloClient, InMemoryCache } from '@apollo/client';
import { createProvider } from 'vue-apollo';

const apolloClient = new ApolloClient({
   uri: 'YOUR_GRAPHQL_ENDPOINT',
   cache: new InMemoryCache(),
 });

provide(createProvider(apolloClient));

5. GraphQL Mesh:

Use GraphQL Mesh for unified APIs from various sources.

sources:
   - name: REST_API
     handler:
       openapi:
         source: http://api.example.com/openapi.json
         link: http://api.example.com/docs

6. Configuration Example — React.js:

Implement Apollo Client with React.js and Hooks.

// In your React.js component
import { ApolloProvider, ApolloClient, InMemoryCache } from '@apollo/client';
const client = new ApolloClient({
   uri: 'YOUR_GRAPHQL_ENDPOINT',
   cache: new InMemoryCache(),
});

<ApolloProvider client={client}>
   {/* Your App Component */}
</ApolloProvider>

This expert-level GraphQL cheatsheet introduces federation, custom scalars, schema stitching, and advanced integrations with Vue.js and React.js. It also mentions GraphQL Mesh for handling multiple data sources

NEED MORE INFORMATION RELATED TO GraphQL. CARRY ON

1. DataLoader for Batch Loading:

Optimize data fetching using DataLoader for batch loading.

// In your DataLoader setup
const { DataLoader } = require('dataloader');
const batchLoadFn = async (keys) => {
   // Fetch data for keys in batch
   const results = await fetchBatchData(keys);
   return results; 
};
const dataLoader = new DataLoader(batchLoadFn);

2. Authorization with Directives:

Implement custom directives for fine-grained authorization.

directive @hasRole(role: String) on FIELD_DEFINITION

type Query {
   adminData: String @hasRole(role: "ADMIN")
   userData: String @hasRole(role: "USER")
}

3. Subscription Handling:

Add real-time capabilities with GraphQL subscriptions.

// In your Apollo Server setup
const { ApolloServer, PubSub } = require('apollo-server');
const pubsub = new PubSub();
const server = new ApolloServer({
   typeDefs,
   resolvers,
   context: { pubsub },
   subscriptions: { path: '/subscriptions' },
})

4. Performance Monitoring:

Integrate GraphQL-specific performance monitoring tools.

// Use Apollo Engine or other monitoring tools
const { ApolloServer } = require('apollo-server');
const server = new ApolloServer({
   // ...
   engine: {
     apiKey: 'YOUR_APOLLO_ENGINE_API_KEY',
   },
});

5. Configuration Example — Angular:

Set up Apollo Client with Angular.

// In your Angular module
import { APOLLO_OPTIONS } from 'apollo-angular';
import { ApolloClientOptions, InMemoryCache } from '@apollo/client/core';
const uri = 'YOUR_GRAPHQL_ENDPOINT';
const cache = new InMemoryCache();
export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
   return {
     link: httpLink.create({ uri }),
     cache,
   };
}
providers: [
   {
     provide: APOLLO_OPTIONS,
     useFactory: createApollo,
     deps: [HttpLink],
   },
]

6. DataLoader for Efficient N+1 Problem:

Use DataLoader to address the N+1 query problem efficiently.

In your DataLoader setup
const { DataLoader } = require('dataloader');
const batchLoadFn = async (keys) => {
   // Fetch data for keys efficiently
   const results = await fetchBatchData(keys);
   return results;
 };
const dataLoader = new DataLoader(batchLoadFn, { cache: false });

Bonus Architect In The End

1. GraphQL with Vue.js:

- src
  - assets
  - components
  - graphql
    - queries
    - mutations
  - views
  - router
  - store
  - plugins
  - utils
  - App.vue
  - main.js

2. GraphQL with React:

- src
  - components
  - containers
  - graphql
    - queries
    - mutations
  - pages
  - context
  - services
  - styles
  - utils
  - App.js
  - index.js

3. GraphQL with Node.js:

- src
  - controllers
  - models
  - graphql
    - types
    - resolvers
  - services
  - config
  - routes
  - middleware
  - utils
  - index.js

4. GraphQL with Angular:

- src
  - app
    - components
    - services
    - graphql
      - queries
      - mutations
    - models
  - assets
  - environments
  - styles
  - utils