Class as an argument-CodePudding

I've just started using typescript and faced with the next implementation issue. I'm trying to implement a class that takes another class as an argument. the issue is that it can be any class, but I want to specify some possible class properties or methods. Let's say that this class can have singleton static property. I try to use Class generic:

type Class<T> = new (...args: any[]) => T;

class ClassResource {
  private _resource;
  private _singleton;
  
  constructor(resource: Class<any>) {
    this._resource = resource;
    this._singleton = resource.singleton;
  }

  // some methods

  getClassInstance() {
    return new this._resource();
  }
}

but got the next error:

Property 'singleton' does not exist on type 'Class'

How can I correctly type this "abstract" class and describe only some specific possible properties, but not limited to them?

CodePudding user response：

All you have to do is mention in your type that the class must have a singleton property.


type _Class<T>= new (...args: any[]) => T;

type ClassType<T> =  _Class<T> & {
    singleton: T
}

class ClassResource {
  private _resource;
  private _singleton;
  
  constructor(resource: ClassType<any>) {
    this._resource = resource;
    this._singleton = resource.singleton;
  }

  // some methods

  getClassInstance() {
    return new this._resource();
  }
}


class A {
    
    static singleton = new A();

    getHello() {
        return ''
    }
}

new ClassResource(A); //works

class B  {
    getHello() {
        return ''
    }
}

new ClassResource(B); // doesn't work