每位开发者都应该知道的 7 种 Node.js 设计模式

// 复杂模块class ComplexModule {  initialize() {    // 复杂的初始化逻辑...  }  operation1() {    // 复杂操作 1  }  operation2() {    // 复杂操作 2  }}// 客户端代码const complexModule = new ComplexModule();complexModule.initialize();complexModule.operation1();complexModule.operation2();

// 在复杂模块中使用门面模式class ModuleFacade {  constructor() {    this.complexModule = new ComplexModule();  }  performOperations() {    this.complexModule.initialize();    this.complexModule.operation1();    this.complexModule.operation2();  }}// 客户端代码const moduleFacade = new ModuleFacade();moduleFacade.performOperations();

class ConfigManager {  constructor() {    this.databaseConfig = { /* 数据库配置 */ };    this.apiKey = "your_api_key";    // 其他应用配置  }
  static getInstance() {    if (!this.instance) {      this.instance = new ConfigManager();    }    return this.instance;  }
  getDatabaseConfig() {    return this.databaseConfig;  }
  getApiKey() {    return this.apiKey;  }  // 其他获取配置的方法}
// 客户端const configManager = ConfigManager.getInstance();
// 访问配置const databaseConfig = configManager.getDatabaseConfig();const apiKey = configManager.getApiKey();

class OldSystem {  request() {    return "Old System Request";  }}

class NewSystem {  newRequest() {    return "New System Request";  }}
class Adapter {  constructor(newSystem) {    this.newSystem = newSystem;  }
  request() {    return this.newSystem.newRequest();  }}

// 老系统的使用const oldSystem = new OldSystem();console.log(oldSystem.request()); // 输出：Old System Request
// 通过适配器使用新系统const newSystem = new NewSystem();const adapter = new Adapter(newSystem);console.log(adapter.request()); // 输出: New System Request

class UserBuilder {  constructor(name) {    this.name = name;    this.email = null;    this.address = null;  }
  withEmail(email) {    this.email = email;    return this; // 通过返回 this 实现方法的链式调用  }
  withAddress(address) {    this.address = address;    return this;  }
  build() {    // 验证和构造用户对象    const user = new User({      name: this.name,      email: this.email,      address: this.address,    });    return user;  }}
// 客户端代码const user1 = new UserBuilder('John')  .withEmail('john@example.com')  .withAddress('123 Main St.')  .build();
console.log(user1); // 打印完整的用户对象的值

// Shape 接口class Shape {  draw() {}}

// Shape 接口的具体实现class Circle extends Shape {  draw() {    console.log("Drawing Circle");  }}class Square extends Shape {  draw() {    console.log("Drawing Square");  }}class Triangle extends Shape {  draw() {    console.log("Drawing Triangle");  }}

// ShapeFactory 类负责创 Shape 的实例class ShapeFactory {  createShape(type) {    switch (type) {      case 'circle':        return new Circle();      case 'square':        return new Square();      case 'triangle':        return new Triangle();      default:        throw new Error('Invalid shape type');    }  }}

// 客户端代码使用 ShapeFactory 来创建 Shapeconst shapeFactory = new ShapeFactory();const circle = shapeFactory.createShape('circle');circle.draw(); // 输出：画圆const square = shapeFactory.createShape('square');square.draw(); // 输出：画正方形const triangle = shapeFactory.createShape('triangle');triangle.draw(); // 输出：画三角形

// 原型对象const animalPrototype = {  type: 'unknown',  makeSound: function () {    console.log('Some generic sound');  },  clone: function () {    return Object.create(this); // 使用 Object.create() 进行克隆  },};

// 基于原型的自定义实例const dog = animalPrototype.clone();dog.type = 'Dog';dog.makeSound = function () {  console.log('Woof!');};
const cat = animalPrototype.clone();cat.type = 'Cat';cat.makeSound = function () {  console.log('Meow!');};

// 使用自定义实例的客户端代码dog.makeSound(); // 输出：Woof!cat.makeSound(); // 输出：Meow!

const target = {  name: 'Alice',  sayHello() {    console.log(Hello, my name is ${this.name} );  },};const handler = {  get(target, prop, receiver) {    console.log(Property ${prop} accessed );    return Reflect.get(target, prop, receiver);  },  set(target, prop, value, receiver) {    console.log(Property ${prop} set to ${value} );    return Reflect.set(target, prop, value, receiver);  },};const proxy = new Proxy(target, handler);proxy.name; // 输出：访问属性名proxy.sayHello(); // 输出：访问属性方法 sayHello                  //        Hello, my name is Aliceproxy.name = 'Bob'; // 输出：属性名设置为 Bob