selectDomain.ts

type Empty = undefined;
const Empty = undefined;

type Pending = 'Pending';
const Pending = 'Pending';

interface CrmUser {
  domain: string;
}

type StoreState = {
  crmData: CrmUser | Empty | Pending;
}

const selectDomain = ({ crmData }: StoreState) => crmData && crmData !== Pending ? crmData.domain : undefined;