1、全局安装typescript

npm install typescript -g 

2、全局安装ts-node

npm install ts-node -g

3、demo.ts

/**
*  B中代码的实现是依赖A的，两者之间的耦合度非常高，当两者之间的业务逻辑复杂程度增加的情况下
*  维护成本与代码的可读性都会随着增加，并且很难再多引入额外的模块进行功能扩展
*/class A {name: stringconstructor(name:string){this.name = name;}
}class B {age: numberentity: Aconstructor (age: number) {this.age = age;this.entity = new A ('test');}
}const c = new B(18);console.log(c.entity.name);

4、demo.ts

// 通过中间件方式来收集依赖，实现解耦，减少维护成本class A {name: stringconstructor(name: string){this.name = name;}
}class C {name: stringconstructor(name: string){this.name = name;}
}// 中间件用于解耦
class Container {modules: anyconstructor () {this.modules = {};}provide(key: string, modules: any){this.modules[key] = modules;}get(key:string){return this.modules[key];}
}// 实例化中间件类，依赖注入
const mo = new Container();
mo.provide('a', new A('test1'));
mo.provide('c', new C('test2'));class B {a: anyc:anyconstructor(container: Container){this.a = container.get('a');this.c = container.get('c');}
}const b = new B(mo);console.log(b.a.name);
console.log(b.c.name);