FactoryType typescript

factory.ts

import Axios, { AxiosInstance } from 'axios';

abstract class BaseRequest {
  abstract request(): AxiosInstance;
}

class Host1 extends BaseRequest {
  request(): AxiosInstance { throw new Error('not implemented'); }
  // todo
  buyProduct() {
    return this.request().post('...');
  }
}

class Host2 extends BaseRequest {
  request(): AxiosInstance { throw new Error('not implemented'); }
  // todo
  getItem() {
    return this.request().post('....');
  }
}

export enum AXIOSES {
  HOST1 = 'HOST1',
  HOST2 = 'HOST2',
}

export type RequestType<X extends keyof typeof AXIOSES> = 
X extends AXIOSES.HOST1 ? Host1 :
X extends AXIOSES.HOST2 ? Host2 : BaseRequest;

export class AxiosFactory {
  
  static get<K extends keyof typeof AXIOSES>(name: K): RequestType<K> {
    if (name === AXIOSES.HOST1) {
      return new Host1() as RequestType<K>;
      // acceptable casting
    } else if (name === AXIOSES.HOST2) {
      return new Host2() as RequestType<K>;
    }
    throw new Error(`name not recognized ${name}`);
  }

}

const a = AxiosFactory.get(AXIOSES.HOST1);
const b = AxiosFactory.get(AXIOSES.HOST2);
a.buyProduct(); // typecheck
b.getItem(); // typecheck