code: func GetVM(structPtr interface{}) *ViewModel {
  	vm, ok := vMap[structPtr]
  	if !ok {
  		panic("GetVM: Vue not registerd yet")
  	}
  	return vm
  }
docs: // GetVM returns coresponding VueJS instance from a gopherjs struct pointer
  // (the underlying ViewModel data), this function is mainly in
  // gopherjs struct method functions to reference the `VueJS instance`