dto.example.ts

const api = {
  get(p) {return p},
  post() {},
  patch() {},
  put() {},
  dele() {},
}

class Resource {
  constructor(private api: any, private resourceUri: string) {}

  private withId(id) {
    return `${this.resourceUri}/${id}`
  }

  fetchAll() {
    return this.api.get(this.resourceUri)
  }

  fetch(id: string) {
    return this.api.get(this.withId(id))
  }

  create(data: any) {
    return this.api.post(this.resourceUri, data)
  }

  save(data: any) {
    return this.api.put(this.resourceUri, data)
  }

  update(data: any) {
    return this.api.patch(this.resourceUri, data)
  }

  destroy(data: any) {
    return this.api.delete(this.resourceUri, data)
  }
}

class Customer extends Resource {
  constructor(api, resourceUri) {
    super(api, resourceUri)
  }
}

const customerModel = new Customer(api, 'customers')

console.log(customerModel.fetchAll())
console.log(customerModel.fetch('1'))