🎄 Advent of Code 2024 Solutions

My solutions to the Advent of Code 2024 challenges, implemented in TypeScript with a focus on clean, maintainable code.

Features • Setup • Usage • Development

Features

• 🚀 Automatic Input Fetching - Downloads puzzle inputs with session token
• ✅ Answer Validation - Verifies solutions against AoC API
• 📝 Type Safety - Full TypeScript with strict checking
• 🔄 Hot Reloading - Instant feedback during development
• 🧪 Consistent Structure - Standardized solution template
• 💾 Input Caching - Offline development support
• ⚡ Performance Tracking - Solution execution timing
• 🛠️ Developer Tools - ESLint, Prettier, and more

Prerequisites

• Node.js 20.x or later
• npm 9.x or later
• Advent of Code session token

Setup

1. Clone and Install

   git clone [your-repo-url]
   cd advent-of-code_2024
   npm install

2. Configure Environment

   # Create .env file
   echo "AOC_SESSION=your_session_token_here" > .env

   To get your session token:

   1. Log into Advent of Code
   2. Open DevTools (F12) → Application → Storage → Cookies
   3. Copy the 'session' cookie value

Project Structure

advent-of-code_2024/
├── solutions/           # Daily puzzle solutions
│   ├── day-{N}/        # Individual day solutions (1-25)
│   │   └── index.ts    # Solution implementation
│   └── template/       # Solution template files
├── utils/              # Shared utilities
│   ├── cache.ts        # Input caching functionality
│   ├── checkAnswer.ts  # Solution validation
│   ├── dates.ts        # Date handling utilities
│   ├── errors.ts       # Custom error types
│   ├── getInput.ts     # Puzzle input fetcher
│   ├── index.ts        # Utility exports
│   ├── performance.ts  # Timing utilities
│   └── runner.ts       # Solution runner
├── scripts/            # Project automation
│   └── create-day.ts   # Solution scaffolding
├── templates/          # Project templates
├── dist/              # Compiled output
├── .cache/            # Cached puzzle inputs
└── node_modules/      # Dependencies

Key Directories

• solutions/: Contains daily puzzle solutions, each in its own directory with a standardized structure
• utils/: Shared utilities for input handling, performance tracking, and solution validation
• scripts/: Automation tools for project management and solution creation
• templates/: Template files for generating new solutions
• dist/: Compiled TypeScript output
• .cache/: Local cache for puzzle inputs (git-ignored)

Solution Structure

Each day's solution follows a consistent pattern:

solutions/day-N/
└── index.ts           # Main solution file containing:
    ├── formatInput()  # Input parser
    ├── solvePart1()   # Part 1 solution
    └── solvePart2()   # Part 2 solution

The solution template includes:

• Strong TypeScript types
• Error handling with custom AoCError
• Performance tracking via the timed() wrapper
• Standardized input parsing
• Consistent error reporting

This structure ensures consistency across solutions while maintaining clean separation of concerns and reusable utilities.

Running Solutions

# Run specific day
DAY=N npm run start:day    # N = 1-25

# Run current day
npm run day

# Run latest solution (that you've created; good when you're a day or more behind)
npm run start:latest

# Development mode with hot reload
DAY=N npm run dev

Development

# Format code
npm run format

# Lint code
npm run lint
npm run lint:fix

# Build project
npm run build

# Run with test input
DAY=N npm run start:day:test

# Run current day with test input
npm run day:test

# Run latest solution with test input (that you've created; good when you're a day or more behind)
npm run start:latest:test

# Development mode with test input
DAY=N npm run dev:test

Creating Solution Files

The project includes scripts to create the necessary file structure for solutions:

# Create a single day's files
npm run new N      # Replace N with day number (1-25)

# Create files for all 25 days at once
npm run new:all

Tech Stack

• Language: TypeScript 5.7
• Runtime: Node.js 20.x
• Module System: ESM
• Development:
  • ESLint
  • Prettier
  • tsx (for hot reloading)

Caching

Input files are cached in /dist/.cache/:

• Minimizes API requests
• Enables offline work
• Improves performance
• Git-ignored by default

License

ISC License

Author

Taylor Sabbag

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