Type GraphQL Query Overview

Type GraphQL Query is a powerful library that allows you to build GraphQL APIs using TypeScript classes and decorators. It automatically generates GraphQL schemas, resolvers, queries, mutations, and subscriptions from your TypeScript code.

What You’ll Learn

This documentation will help you understand:

✅ How to define GraphQL types using TypeScript classes
✅ How to create queries, mutations, and subscriptions
✅ How to implement filtering, sorting, and paging
✅ How to manage relationships between entities
✅ How to implement authorization and access control
✅ How to use advanced features like aggregations, search, and translations

Key Features

Type GraphQL Query provides a comprehensive set of features for building GraphQL APIs:

Feature	Description
🎯 Type Safety	Full TypeScript support with compile-time type checking
🎨 Decorators	Use decorators to define GraphQL types and fields
⚡ Code Generation	Automatic GraphQL schema and resolver generation
✅ Validation	Built-in validation support for inputs
🔍 Filtering	Powerful filtering system with complex conditions
📊 Sorting & Paging	Built-in sorting and paging support
🔗 Relations	Easy relationship management between entities
🔐 Authorization	Built-in authorization and access control
🔄 Subscriptions	Real-time updates with GraphQL subscriptions
🌍 Translations	Multi-language support for fields
🔎 Search	Full-text search capabilities
📈 Aggregations	Aggregate queries for analytics

Core Concepts

DTOs (Data Transfer Objects)

Define your GraphQL types using TypeScript classes with decorators:

import { ObjectType, ID } from '@lib/type-graphql';
import { EnhancedField, IDField } from '@lib/type-graphql-query';

@ObjectType()
export class Product {
  @IDField(() => ID)
  id: string;

  @EnhancedField(() => String)
  name: string;
}

Queries

Automatically generated queries with filtering, sorting, and paging:

query {
  products(
    filter: { name: { like: "%laptop%" } }
    sorting: [{ field: name, direction: ASC }]
    paging: { limit: 10, offset: 0 }
  ) {
    nodes {
      id
      name
    }
    totalCount
  }
}

Mutations

Automatically generated mutations for create, update, delete, and upsert operations:

mutation {
  createOneProduct(input: { name: "New Product" }) {
    id
    name
  }
}

Relations

Define relationships between entities:

@Relation('category', () => Category)
category: Category;

Quick Start

Ready to get started? Follow these steps:

📖 Getting Started - Set up and create your first DTO
📝 DTOs - Learn how to define data transfer objects
🔍 Queries - Understand query operations
✏️ Mutations - Learn about mutations

Documentation Structure

Our documentation is organized to help you learn progressively:

Fundamentals

DTOs - Define your data structures
Types - GraphQL type system
QueryService - Core service interface
Assemblers - DTO to Entity translation

GraphQL Operations

Resolvers - How resolvers work
Queries - Query operations with filtering, sorting, paging
Mutations - Create, update, delete operations
Subscriptions - Real-time updates
ListenChanges - Database change notifications

Configuration

QueryOptions - Configure query behavior
ContextFilter - Context-aware filtering

Advanced Features

Relations - Entity relationships
Aggregations - Aggregate queries
Search - Full-text search
Translations - Multi-language support
Soft Delete - Soft delete functionality

Security & Control

Authorization - Access control
Hooks - Lifecycle hooks

Extensions

DataLoaders - N+1 query optimization
Federation - GraphQL federation

Next Steps

Ready to dive in? Start with these essential topics:

🚀 Getting Started - Quick start guide
📝 DTOs - Learn how to define types
🔍 Queries - Understand query operations
✏️ Mutations - Learn about mutations

API Overview - Understand the API architecture
Code Structure - Learn about module organization
Development Guide - Development workflow