class Product {
  name: string
  constructor(name) {
    this.name = name
  }
  fn1() {
    console.log('prod')
  }
  fn2() {
    console.log('prod-2')
  }
}
// 工厂
class Creator {
  create(name: string): Product {
    return new Product(name)
  }
}
// test
const creator = new Creator();
const p1 = creator.create('p1');
const p2 = creator.create('p2');
const p3 = creator.create('p3');
const p4 = creator.create('p4');

interface IProduct {
  name: string
  fn1: () => void
  fn2: () => void
}
class Product1 implements IProduct {
  name: string
  constructor(name: string) {
    this.name = name
  }
  fn1() {}
  fn2() {}
}
class Product2 implements IProduct {
  name: string
  constructor(name: string) {
    this.name = name
  }
  fn1() {}
  fn2() {}
}
class Creator {
  // 符合依赖倒置原则，我们返回的不是Product1或Product2，而是返回接口类型IProduct
  create(type: string, name: string): IProduct {
    // new 时的一些逻辑
    if (type === 'p1') return new Product1(name)
    if (type === 'p2') return new Product2(name)
    throw new Error('Invalid type')
  }
}
// test
const creator = new Creator();
const p1 = creator.create('p1', 'name1')
const p11 = creator.create('p1', 'name11')
const p2 = creator.create('p2', 'name2')

是否符合设计原则

• 工厂和类分离，解耦
• 可以扩展多个类（派生类，或平行的类）
• 工厂的创建逻辑也可以自由扩展