In this video, I revisit the command pattern and show you one change that makes this pattern really flexible: going from the state being the ground truth to the transactions being the ground truth. The code I worked on in this example is available here: https://github.com/ArjanCodes/2021-command-transactions. Part 1 of this miniseries: https://www.youtube.com/watch?v=FM71_a3txTo. 💡 Here's my FREE 7-step guide to help you consistently design great software: https://arjancodes.com/designguide. 🎓 Courses: The Software Designer Mindset: https://www.arjancodes.com/mindset The Software Designer Mindset Team Packages: https://www.arjancodes.com/sas The Software Architect Mindset: Pre-register now! https://www.arjancodes.com/architect Next Level Python: Become a Python Expert: https://www.arjancodes.com/next-level-python The 30-Day Design Challenge: https://www.arjancodes.com/30ddc 🛒 GEAR & RECOMMENDED BOOKS: https://kit.co/arjancodes. 💬 Join my Discord server here: https://discord.arjan.codes/ 🐦Twitter: https://twitter.com/arjancodes 🌍LinkedIn: https://www.linkedin.com/company/arjancodes 🕵Facebook: https://www.facebook.com/arjancodes 👀 Channel code reviewer board: - Yoriz - Ryan Laursen - Sybren A. Stüvel - Dale Hagglund 🔖 Chapters: 0:00 Intro 1:02 Recap of last week's example 2:45 States vs. transactions 4:05 Using transactions as the ground truth 10:23 Simplifying the undo/redo mechanism 12:02 Changing the balance value to a cache 15:03 More examples of transaction-based systems #arjancodes #softwaredesign #python DISCLAIMER - The links in this description might be affiliate links. If you purchase a product or service through one of those links, I may receive a small commission. There is no additional charge to you. Thanks for supporting my channel so I can continue to provide you with free content each week!