refactoring-patterns

npx skills add cosmicstack-labs/mercury-agent-skills --skill refactoring-patterns --agent claude-code

Same command for any agent — swap --agent for codex, cursor, copilot.

# Refactoring Patterns Systematically improve code without changing its behavior. ## The Refactoring Workflow 1. **Identify** a code smell or pain point 2. **Ensure** you have tests (write them first if not) 3. **Apply** one refactoring at a time 4. **Test** after each change (green = continue, red = revert) 5. **Commit** — small, focused, descriptive 6. **Repeat** ## Extract Method **When**: A method does multiple things or is too long. **How**: Find a cohesive block → extract to new method → call it. ```javascript // Before function processOrder(order) { const total = order.items.reduce((sum, i) => sum + i.price, 0); const tax = total * 0.08; const discount = order.coupon ? total * 0.1 : 0; return total + tax - discount; } // After function processOrder(order) { const subtotal = calculateSubtotal(order); const tax = calculateTax(subtotal); const discount = calculateDiscount(order, subtotal); return subtotal + tax - discount; } ``` ## Replace Conditional with Polymorphism **When**: Switch/if-else chains based on type grow too long. ```javascript // Before function calculateShipping(order) { if (order.type === 'standard') return order.weight * 0.5; if (order.type === 'express') ret