slug: design-patterns
title: "Design Patterns — Factory, Observer, Strategy, and Friends"
version: 1.0.0
description: "Learn six essential design patterns with practical TypeScript examples."
category: fundamentals
tags: [design-patterns, oop, architecture, gang-of-four, software-design]
difficulty: intermediate

xp:
  read: 15
  walkthrough: 40
  exercise: 25
  quiz: 20
  quiz-perfect-bonus: 10
  game: 25
  game-perfect-bonus: 10

time:
  quick: 5
  read: 25
  guided: 60

prerequisites: [solid-principles]
related: [clean-code, system-design]

triggers:
  - "What are design patterns?"
  - "When should I use the Factory pattern?"
  - "What is the Observer pattern?"
  - "How do I choose the right design pattern?"

visuals:
  diagrams: [diagram-mermaid, diagram-architecture]
  quiz-types: [quiz-matching, quiz-timed-choice]
  game-types: [memory-match, classify]
  playground: javascript
  slides: true

sources:
  - url: "https://refactoring.guru/design-patterns"
    label: "Refactoring Guru"
    type: docs
  - url: "https://www.oreilly.com/library/view/head-first-design/0596007124/"
    label: "Head First Design Patterns"
    type: docs