Translation Comparison - refactor

Code is hard to understand or modify
Duplicated logic across files
Functions/classes are too large
Technical debt reduction
Before adding new features

代码难以理解或修改
多个文件中存在重复逻辑
函数/类过于庞大
需要减少技术债务
添加新功能之前

Refactoring Process

重构流程

Ensure tests exist - Add tests before refactoring
Small steps - Make incremental changes
Run tests - Verify after each change
Commit often - Keep changes reversible

确保测试存在 - 重构前先添加测试
小步迭代 - 进行增量式修改
运行测试 - 每次修改后验证
频繁提交 - 保持修改可回滚

Common Refactorings

常见重构手法

Extract Function

提取函数

javascript

// Before
function processOrder(order) {
  // 50 lines of validation
  // 30 lines of calculation
  // 20 lines of notification
}

// After
function processOrder(order) {
  validateOrder(order);
  const total = calculateTotal(order);
  notifyCustomer(order, total);
}

javascript

// Before
function processOrder(order) {
  // 50 lines of validation
  // 30 lines of calculation
  // 20 lines of notification
}

// After
function processOrder(order) {
  validateOrder(order);
  const total = calculateTotal(order);
  notifyCustomer(order, total);
}

Replace Conditionals with Polymorphism

用多态替换条件语句

javascript

// Before
function getPrice(type) {
  if (type === "regular") return basePrice;
  if (type === "premium") return basePrice * 1.5;
  if (type === "vip") return basePrice * 0.8;
}

// After
const pricingStrategies = {
  regular: (base) => base,
  premium: (base) => base * 1.5,
  vip: (base) => base * 0.8,
};
const getPrice = (type) => pricingStrategies[type](basePrice);

javascript

// Before
function getPrice(type) {
  if (type === "regular") return basePrice;
  if (type === "premium") return basePrice * 1.5;
  if (type === "vip") return basePrice * 0.8;
}

// After
const pricingStrategies = {
  regular: (base) => base,
  premium: (base) => base * 1.5,
  vip: (base) => base * 0.8,
};
const getPrice = (type) => pricingStrategies[type](basePrice);

Remove Duplication

移除重复代码

javascript

// Before
function getUserName(user) {
  return user?.profile?.name ?? "Unknown";
}
function getOrderName(order) {
  return order?.customer?.name ?? "Unknown";
}

// After
const getName = (obj, path) => path.reduce((o, k) => o?.[k], obj) ?? "Unknown";
const getUserName = (user) => getName(user, ["profile", "name"]);
const getOrderName = (order) => getName(order, ["customer", "name"]);

javascript

// Before
function getUserName(user) {
  return user?.profile?.name ?? "Unknown";
}
function getOrderName(order) {
  return order?.customer?.name ?? "Unknown";
}

// After
const getName = (obj, path) => path.reduce((o, k) => o?.[k], obj) ?? "Unknown";
const getUserName = (user) => getName(user, ["profile", "name"]);
const getOrderName = (order) => getName(order, ["customer", "name"]);

Code Smells

代码异味

Smell	Symptom	Refactoring
Long Function	>20 lines	Extract Function
Large Class	>200 lines	Extract Class
Duplicate Code	Same logic repeated	Extract and reuse
Long Parameter	>3 params	Use object/builder
Feature Envy	Uses other class's data	Move method
Primitive Obsession	Strings for everything	Create value objects

异味类型	表现特征	重构手法
过长函数	超过20行	提取函数
过大类	超过200行	提取类
重复代码	相同逻辑重复出现	提取并复用
参数过多	超过3个参数	使用对象/构建器
特性依恋	过度依赖其他类的数据	移动方法
基本类型偏执	所有数据都用字符串表示	创建值对象

Quality Metrics

质量指标

Cyclomatic Complexity - Keep under 10 per function
Nesting Depth - Max 3 levels
Function Length - Under 20 lines preferred
File Length - Under 300 lines preferred

圈复杂度 - 每个函数保持在10以下
嵌套深度 - 最多3层
函数长度 - 建议不超过20行
文件长度 - 建议不超过300行

Safety Checklist

安全检查清单

Input: "This function is too long" Action: Identify logical sections, extract into focused functions, verify tests pass

Input: "Reduce duplication in these files" Action: Find common patterns, extract shared utilities, update call sites

输入： "这个函数太长了" 操作： 识别逻辑模块，提取为专注的函数，验证测试通过

输入： "减少这些文件中的重复代码" 操作： 找出通用模式，提取共享工具函数，更新调用位置

refactor

Original

Translation

Code Refactoring

代码重构

When to Use

适用场景

Refactoring Process

重构流程

Common Refactorings

常见重构手法

Extract Function

提取函数

Replace Conditionals with Polymorphism

用多态替换条件语句

Remove Duplication

移除重复代码

Code Smells

代码异味

Quality Metrics

质量指标

Safety Checklist

安全检查清单

Examples

示例