Chain of Responsibility
Passes a request along a chain of handlers. Each handler decides either to process the request or pass it to the next handler in the chain.
Chain of Responsibility: Pass It Down the Line
Giving multiple handlers a chance to process a request, each passing it on if it cannot.
Chain of Responsibility in Production: Middleware
HTTP middleware, event preprocessing, and auth chains in real frameworks.
Advanced Chain: Dynamic and Concurrent Chains
Runtime-reconfigurable chains, async handlers, and chains that split.
Chain of Responsibility: Review & Mastery Quiz
Scenario questions on handlers, middleware, and dynamic chains.
Free Books & Guides
Refactoring.Guru — Chain of Responsibility
The definitive modern guide to the Chain of Responsibility pattern. Clear explanations, UML diagrams, real-world analogies, and code examples in multiple languages.
SourceMaking — Chain of Responsibility
A comprehensive companion guide covering the Chain of Responsibility pattern with detailed rules of thumb, criticisms, and robust code snippets.
GoF Design Patterns — Chain of Responsibility
The original Gang of Four book describing the pattern. Available in the "Design Patterns: Elements of Reusable Object-Oriented Software" on Wikipedia.
Official Documentation
Refactoring.Guru — Chain of Responsibility
The definitive modern guide to the Chain of Responsibility pattern. Clear explanations, UML diagrams, real-world analogies, and code examples in multiple languages.
Wikipedia — Chain of Responsibility Pattern
Wikipedia article explaining the Chain of Responsibility pattern with examples and history.
Video Courses
freeCodeCamp — Design Patterns Course
A comprehensive multi-hour video course covering all major design patterns with implementations in JavaScript and TypeScript.
Design Patterns in Modern JavaScript Playlist
YouTube playlist covering creational, structural, and behavioral patterns with clear code walkthroughs.
Web Dev Simplified — Chain of Responsibility
Clear, concise video tutorials covering design patterns with practical examples.
Practice & Examples
Awesome Low-Level Design (GitHub)
A curated collection of free LLD resources, pattern implementations, and interview problems across multiple languages.
Design Patterns Implementation (GitHub)
The most popular open-source collection of design pattern implementations with detailed explanations.
Refactoring.Guru Examples in Chain of Responsibility
Code examples of the Chain of Responsibility pattern in TypeScript, Python, Java, and more.