🎄 Advent Of Code 🎄

Solutions to the Advent of Code challenges in JavaScript (Node.js).

Requirements

• Node.js >= 22
• npm dependencies installed with npm install
• Optional .env file with AOC_SESSION_COOKIE=your_cookie if you want to scaffold a missing challenge

Warning

Automatic input.txt download is currently disabled in src/template/challengeSetup.js

Getting started

1. Install dependencies with npm install
2. Optionally create a .env file with AOC_SESSION_COOKIE=your_cookie
3. Run npm start <year> <day>
4. If the target challenge does not exist, the project creates the folder and copies the template index.js

Examples:

• npm start 2024 1
• npm start 2025 1

Challenge status per year

Year	Completed days	Status
2022	15/25	🔄 In progress
2023	13/25	🔄 In progress
2024	11/25	🔄 In progress
2025	6/25	🔄 In progress

Notes:

• The 2022 total includes day1 to day9 in src/2022 and archived day10 to day15 in src/2022_backup.
• The 2025 folder currently uses zero-padded names (day01 to day06) and also contains an extra day6 directory.

Project structure

AdventOfCode/
├── index.js                  # Entry point: node index.js <year> <day>
├── .nvmrc                    # Node.js version used by the project
├── eslint.config.js          # Active ESLint flat config
├── .eslintrc.yml             # Legacy ESLint config kept in the repo
├── src/
│   ├── template/             # Template for new challenges
│   │   ├── template.js       #   Base code for a solution
│   │   └── challengeSetup.js #   Auto-setup + input download script
│   ├── 2022/                 # Active 2022 solutions (day1-day9)
│   ├── 2022_backup/          # Archived 2022 solutions (day10-day15)
│   ├── 2023/ (day1-day13)
│   ├── 2024/ (day1-day11)
│   └── 2025/ (day01-day06)
├── package.json
├── .prettierignore
└── .prettierrc

Commands

Command	Description
npm start <year> <day>	Runs index.js with the Node inspector enabled; if the challenge folder does not exist, it scaffolds it from the template
npm test	Runs tests with Mocha (src/**/*.test.js)
npm run lint	Runs ESLint on src/**/*.js using eslint.config.js
npm run debug	Runs with the Node.js inspector (--inspect-brk)
npm run prettier	Runs Prettier on src/**/*.js

Tests

The project uses Mocha + Chai for testing.

npm test

Tests should be placed next to the solutions using the *.test.js pattern.

Technologies

• Runtime: Node.js 22
• Language: JavaScript ES modules
• Testing: Mocha + Chai
• Linting: ESLint flat config + eslint-config-prettier
• Formatting: Prettier