creating instance of a class based on string name of a class

I am trying to create an instance of a class based on string input parameter.

for ex:

class Caller{
  constructor(private factory: IFactory){}
  
  getInstance(productType: string){
    var instance = factory.create(productType);
    console.log(instance);
  }
}



interface IService{}
class ServiceA implements IService{}
class ServiceB implements IService{}

class IFactory{
  create(productType: string): IService;
}

class Factory implements IFactory{
  create(productType: string): IService{
     // I want to return any child service class ServiceA/ServiceB instance here
     // I know I can do conditional instance creation by comparing input string to the type 
     // but don't want to do that
  }
}

I have seen and tried many other similar one's provided on SO, but nothing works for me like: Dynamically loading a typescript class (reflection for typescript)

OR

Creating Instance Of Class Based On ClassName : string

Thanks