How to Work With a Large Legacy Codebase Like a Pro

1. Understand the Nature of Legacy Code:

• Recognize that legacy code results from past decisions and should be handled with care and respect.

2. Be Curious, Not Critical:

• Avoid criticizing the code; instead, be curious and empathetic.
• Seek to learn the reasons behind coding decisions and ask colleagues for explanations.

3. Familiarize Yourself with the Platform:

• Before diving into coding, explore the entire platform, considering aspects like speed and user experience.
• Understand the users' perspectives to better align your work with their needs.

4. Focus on the Most Important Parts:

• Apply the Pareto principle (80/20 rule) to prioritize files and folders in the codebase.
• Concentrate on critical files like config files, folder structures, and test files for better understanding.

5. Study Workflows:

• Learn the flow of operations within the codebase, understanding how components interact.
• Trace how various parts of the codebase connect to enhance your comprehension.

6. Research Libraries and Frameworks:

• Investigate any libraries and frameworks used in the codebase, both internal and external.
• Seek help from colleagues who have experience with these libraries if needed.

7. Understand Hardcoded Code:

• Recognize that some code may appear unnecessary but plays a vital role in control flows or mathematical expressions.
• Document the purpose and reasoning behind such code for future reference.

8. Extend Before Refactoring:

• Rather than immediately refactoring, start by extending the codebase to meet business needs.
• Ensure that any new features added don't inherit the undesirable traits of the legacy codebase.

9. Document Your Journey:

• Document your process of understanding the codebase, from initial setup to exploring its various parts.
• Share this documentation with your team to enhance onboarding and make future work more accessible.

10. Be Patient and Collaborative:
- Take your time to understand the codebase and its context before making significant changes.
- Encourage collaboration and improvements in documentation to benefit both current and future team members.

By following these guidelines, you can navigate a large legacy codebase effectively and deliver the features required by your organization and end users.