Chess

This has been a long and challenging project. It took me two and a half months to complete, but I am so proud to have finished. The journey was full of ups and downs, and it often felt like taking two steps back to take three steps forward.

While I can say that this program was built from scratch, I would also like to recognize that I could not have done it without The Odin Project community Discord server. Their help genuinely made all the difference, and for that I am endlessly grateful!

Video Demo

Click here for a Live Demo!

Functionality

• Game Modes
  • Human vs. Human
  • Human vs. Computer
  • Computer vs. Computer
• Colorized Chess Board
• Players move pieces using coordinates like 'a1' or 'e5'
• Red dots indicate legal moves
• Enemy pieces that can be captured have a red background
• When an enemy piece is captured, it gets added to your graveyard
• Illegal moves tell you why they're illegal
• Once a piece is selected, it can be unselected
• The game can be saved to JSON at the beginning of a player's turn
• Upon starting the game, the old, saved game can be loaded
• Full check and Checkmate detection
• Asks for rematch and will replay from the beginning

Other Features of the Code

• The Piece class makes use of the Template Method Design Pattern
• The Cell class makes use of the Null Object Design Pattern
• Factories are used for piece creation
• Slight polymorphism is used for the different game modes
• Supported by 127 RSpec tests

Things to Add Later

• Castling
• En Passant
• Pawn promotion
• Other fancy game moves

The Biggest Challenge

By far, the biggest challenge was wrapping my mind around Object Oriented Design priciples. At first, I tried to write my Ruby code the same way I had written my procedural Javascript code. I thought I was close to the end of the project when I was able to move pieces, but I got stuck because my classes were so jumbled up.

When I went to the TOP Discord multiple great folks said that my program was begging for more classes and my classes were begging to be smarter. I think I had five classes handling EVERYTHING. That's when someone mentioned that they had over thirty classes in their solution to Chess. Obviously I was doing something inefficiently.

This is when I had to swallow my urge to plow forward. I had read about half of Practical Object Oriented Design Principles by Sandi Metz months before getting stuck, and I thought I knew OOP because I understood how messages worked between classes. Then someone told me 99 Bottles of OOP by Sandi Metz might help. And It did!

99 Bottles made me realize that polymorphism was perhaps the most magical aspect of OOP. I also realized that I knew NOTHING about it! So, I read and worked alongside the book for a week or two, then got back to work. It took a few chats on Discord to understand how to apply this new knowledge to my Chess project. However, once the ball was rolling, I took off.

I was able to apply the Template method to my Piece class hierarchy, and it felt great! I was also able to use design paterns and polymorphism in some other places. I must admit that I do not consider myself a master of design patterns and polymorphism. However, what this taught me was that there really is magic to OOP.

Moving forward in my OOP education, I have another book called Head First Design Patterns by Eric Freeman & Elisabeth Robson that goes over these inspiring design patterns in much more depth and detail.

In Conclusion

This was a humbling and massively beneficial project that I don't know if I'll ever forget. This was a tough project to cut my teeth on, but I look forward to returning to this game when I have far more experience.