Text Compare for Code Refactoring | Rune

Code refactoring—improving code structure without changing functionality—is one of the riskiest aspects of software development. How do you know you haven't accidentally broken something? Text comparison helps you verify your changes are intentional and correct.

What is Code Refactoring?

Refactoring means restructuring existing code without changing its external behavior. Common refactoring tasks include:

• Renaming variables for clarity.
• Extracting functions to reduce duplication.
• Simplifying conditional logic.
• Reorganizing file structure.

Why Compare During Refactoring?

Verify Intentional Changes

After refactoring, compare the old and new versions. Every difference should be intentional. Unexpected changes might indicate bugs.

Document Your Changes

A diff file shows exactly what you modified—useful for code reviews and team documentation.

Catch Accidental Modifications

Sometimes refactoring tools or find-replace operations change more than intended. Comparison catches these.

How to Compare Refactored Code

1. Copy your original code before refactoring.
2. Perform your refactoring.
3. Open Rune's Text Compare.
4. Paste original code on the left, refactored code on the right.
5. Enable Character Level comparison.
6. Keep Case Sensitivity on.
7. Review every highlighted change.

Example: Variable Renaming

Before

function calc(d) {
  return d * 0.1;
}

After

function calculateDiscount(price) {
  return price * 0.1;
}

Comparison shows:

• calc → calculateDiscount
• d → price

Both changes are intentional. If something else was highlighted (like the 0.1), you'd know you accidentally modified logic.

Best Practices for Refactoring Comparison

Practice	Why It Matters
Compare before and after each step	Catch issues early
Use character-level for code	Don't miss single-character changes
Keep case sensitivity on	myVar ≠ myvar in most languages
Save the diff	Document your refactoring for team review

When to Be Extra Careful

• Regex-based find-replace: Can have unintended matches.
• IDE auto-refactoring: Usually safe, but worth verifying.
• Large-scale renaming: More surface area for errors.

Conclusion

Refactoring is essential for maintainable code, but it's risky. Text comparison adds a safety net by showing exactly what changed. Use Rune's Text Compare to refactor with confidence.