基于字符串的动态返回类型

Question

是否可以将字符串传递给函数并分配返回的动态类型？

class MyService {
  aMethod(arg) {
    console.log(arg)
  }
}

Container.register('my_service', MyService);

// Internally Container holds a Object 
export interface IServiceInstance {
    name: string;
    type: Function;
    instance: Object;
}

const myServiceInstance = Container.get('my_service')

// myServiceInstance should be detected as type of MyService class
myServiceInstance.aMethod('Hello World') 

// Currently I use it like this. But if it is possible I want to get rid of that
const myServiceInstance = (Container.get('my_service') as MyService)

Answer 1

您可以通过字符串常量扩展容器类型以添加​​方法特化：

// In a library for example
declare class ContainerClass {
    register<T>(name: string, ctor: new ()=> T): void;
    get (name: string) : any;
}
let Container: ContainerClass ;


// In your app
class MyService {
    aMethod(arg) {
      console.log(arg)
    }
  }

Container.register('my_service', MyService);
interface ContainerClass {
    get (name: 'my_service') : MyService;
}
Container.get('my_service').aMethod("");

这利用了一个类型（接口或类）可以通过在相同的命名空间中声明一个具有相同名称的接口来扩展的事实。