Mock up a Game: Apply Design Patterns

Assignment Overview

Put your newfound knowledge of design patterns to work by creating a simple game prototype! This assignment will help you practice both architectural patterns (inheritance or composition) and the pub/sub communication system you learned about in the lesson.

Instructions

Create a simple game representation that demonstrates the design patterns from this lesson. Your game should be functional but doesn't need complex graphics \u2013 focus on the underlying architecture and communication patterns.

Requirements

Choose Your Architecture Pattern:

Option A: Use class-based inheritance (like the GameObject → Movable → Hero example)
Option B: Use composition (like the factory function approach with mixed behaviors)

Implement Communication:

Include an EventEmitter class for pub/sub messaging
Set up at least 2-3 different message types (like PLAYER_MOVE, ENEMY_SPAWN, SCORE_UPDATE)
Connect user input (keyboard/mouse) to game events through the event system

Game Elements to Include:

At least one player-controlled character
At least one other game object (enemy, collectible, or environmental element)
Basic interaction between objects (collision, collection, or communication)

Suggested Game Ideas

Simple Games to Consider:

Snake Game \u2013 Snake segments follow the head, food spawns randomly
Pong Variation \u2013 Paddle responds to input, ball bounces off walls
Collector Game \u2013 Player moves around collecting items while avoiding obstacles
Tower Defense Basics \u2013 Towers detect and shoot at moving enemies

Code Structure Guidelines

javascript

// Example starting structure
const Messages = {
  // Define your game messages here
};

class EventEmitter {
  // Your event system implementation
}

// Choose either class-based OR composition approach
// Class-based example:
class GameObject { /* base properties */ }
class Player extends GameObject { /* player-specific behavior */ }

// OR Composition example:
const gameObject = { /* base properties */ };
const movable = { /* movement behavior */ };
function createPlayer() { /* combine behaviors */ }

Testing Your Implementation

Verify your code works by:

Testing that objects move or change when events are triggered
Confirming that multiple objects can respond to the same event
Checking that you can add new behaviors without modifying existing code
Ensuring keyboard/mouse input properly triggers game events

Submission Guidelines

Your submission should include:

JavaScript file(s) with your game implementation
HTML file to run and test your game (can be simple)
Comments explaining which pattern you chose and why
Brief documentation of your message types and what they do

Rubric

Criteria	Exemplary (3 points)	Adequate (2 points)	Needs Improvement (1 point)
Architecture Pattern	Correctly implements either inheritance OR composition with clear class/object hierarchy	Uses chosen pattern with minor issues or inconsistencies	Attempts to use pattern but implementation has significant problems
Pub/Sub Implementation	EventEmitter works correctly with multiple message types and proper event flow	Basic pub/sub system works with some event handling	Event system present but doesn't work reliably
Game Functionality	Three or more interactive elements that communicate through events	Two interactive elements with basic event communication	One element responds to events or basic interaction
Code Quality	Clean, well-commented code with logical organization and modern JavaScript	Generally well-organized code with adequate comments	Code works but lacks organization or clear commenting

Bonus Points:

Creative game mechanics that showcase interesting uses of the patterns
Multiple input methods (keyboard AND mouse events)
Scalable architecture that would be easy to extend with new features