Structural issues that make code hard to maintain, extend, or understand
Structural problems that indicate deeper issues in your codebase design
Object-oriented design problems that make code hard to change and test
Violations of fundamental design principles that lead to rigid, fragile code
Code paths that are too complex to understand, test, or maintain safely
Objective limits that signal when code needs refactoring
Methods should fit on one screen
Classes should have single responsibility
Consider using an options object
Extract functions or use early returns
Too many paths to test reliably
Extract to a shared function
See how Refactoring Advisor identifies problems and suggests specific patterns to apply
function processOrder(order) {
// Validate order
if (!order.items || order.items.length === 0) {
throw new Error('Empty order')
}
if (!order.customer) {
throw new Error('No customer')
}
// Calculate totals
let subtotal = 0
for (const item of order.items) {
subtotal += item.price * item.quantity
}
const tax = subtotal * 0.1
const total = subtotal + tax
// Apply discounts
let discount = 0
if (order.customer.isPremium) {
discount = total * 0.15
} else if (subtotal > 100) {
discount = total * 0.05
}
return total - discount
}Method doing 4 things: validation, calculation, tax, discounts
function processOrder(order) {
validateOrder(order)
const subtotal = calculateSubtotal(order.items)
const total = applyTax(subtotal)
return applyDiscount(total, order.customer)
}
function validateOrder(order) {
if (!order.items?.length) throw new Error('Empty order')
if (!order.customer) throw new Error('No customer')
}
function calculateSubtotal(items) {
return items.reduce((sum, item) =>
sum + item.price * item.quantity, 0)
}Extract Method: each function does one thing well
function calculateShipping(order) {
switch (order.shippingType) {
case 'express':
return order.weight * 5.0 + 15
case 'standard':
return order.weight * 2.5 + 5
case 'economy':
return order.weight * 1.0
case 'freight':
return order.weight * 0.5 + 50
default:
throw new Error('Unknown type')
}
}Switch statement that grows with each new shipping type
interface ShippingStrategy {
calculate(weight: number): number
}
const shippingStrategies: Record<string, ShippingStrategy> = {
express: { calculate: w => w * 5.0 + 15 },
standard: { calculate: w => w * 2.5 + 5 },
economy: { calculate: w => w * 1.0 },
freight: { calculate: w => w * 0.5 + 50 },
}
function calculateShipping(order) {
const strategy = shippingStrategies[order.shippingType]
if (!strategy) throw new Error('Unknown type')
return strategy.calculate(order.weight)
}Strategy pattern: add new types without modifying existing code
class OrderProcessor {
calculateTax(order) {
const subtotal = order.items.reduce((sum, item) =>
sum + item.price * item.quantity, 0)
const taxRate = order.customer.region === 'EU'
? order.customer.country.vatRate
: 0.0
return subtotal * taxRate
}
}OrderProcessor knows too much about Order and Customer internals
class Order {
calculateSubtotal() {
return this.items.reduce((sum, item) =>
sum + item.price * item.quantity, 0)
}
calculateTax() {
return this.calculateSubtotal() * this.customer.getTaxRate()
}
}
class Customer {
getTaxRate() {
return this.region === 'EU' ? this.country.vatRate : 0.0
}
}Move behavior to the class that owns the data
Refactoring Advisor doesn't just measure metrics — it understands design patterns and suggests specific refactoring techniques that will improve your code structure.
Identifies code smells and anti-patterns in your code structure
Suggests specific patterns: Extract Method, Replace Conditional, Move Method
Checks adherence to SRP, OCP, LSP, ISP, and DIP
Measure Metrics
Calculates method/class length and complexity scores
Identify Patterns
Detects code smells and design anti-patterns
Check SOLID
Verifies adherence to design principles
Suggest Refactoring
Recommends specific patterns like Extract Method, Replace Conditional with Polymorphism
Focuses on issues that WILL cause maintenance problems, not style nitpicks
Copy-paste code that must be changed in multiple places
Classes doing too many things, impossible to test
Functions with too many paths to test reliably
Skipped in favor of structural problems
Technical debt compounds exponentially.
Refactoring Advisor catches it early.
Let Refactoring Advisor catch structural issues before they compound. Free for 14 days, no credit card required.