updateItem example no mutation

updateitem.js

selectService(
  context: StateContext<ServiceDetailDialogModel>,
  { payload: {
    serviceName,
    doSelect
  } }: ServiceDetailDialogActions.SelectService) {
  const { serviceHosts } = context.getState();
  // get the index
  const serviceIndex: number = serviceHosts.findIndex(service_ => service_.serviceName === serviceName);
  if (serviceIndex < 0) {
    //throw error or something?
  }
  // clone and update
  const service = {
    ...serviceHosts[serviceIndex],
    selected: doSelect,
    hosts: hosts.map(host => ({
      ...host,
      selected: doSelect
    }))
  };
  ctx.setState(
    patch({
      serviceHosts: updateItem(serviceIndex, service)
    })
  );
}