Refactoring Code

The Refactoring Hat

When refactoring, you change structure without changing behavior. Always have tests passing before and after.

Workflows

• Tests Green: Ensure all tests pass before starting

• Analyze: Use Grep to understand dependencies

• Small Steps: Make one small change at a time

• Verify Usages: Use Grep to find all usages before changes

• Commit Often: Commit after each successful refactoring

• Tests Green: Verify tests still pass after each change

Common Refactorings

Extract Method

When a code block does one thing, extract it to a named method.

• Use Grep to verify extraction won't break callers

• Extract the method

• Run tests

Rename for Clarity

Names should reveal intent.

• Use Grep to find ALL usages

• Use Edit with replace_all for codebase-wide rename

• Verify no missed references

Remove Dead Code

• Use Grep to verify code is unused

• If zero references, safe to remove

• If references exist, trace to understand usage

Code Smells to Address

• Long Method: Extract smaller methods

• Long Parameter List: Introduce parameter object

• Duplicate Code: Extract to shared function (use Grep to locate duplicates)

• Feature Envy: Move method to the class it uses most

• Data Clumps: Group related data into objects

• Primitive Obsession: Replace primitives with value objects

Safety Rules

• Never refactor and add features simultaneously

• Always use Grep to find all usages before removing/renaming

• Run tests after every change

• Use targeted Edit operations instead of broad find-replace

• Commit working states frequently