address-undefined-optional.ts

interface Address {
  lineOne: string;
  lineTwo: string | undefined;
  city: string;
}

type AddressWithOptionalProperties = UndefinedOptional<Address>;
const address: Address = {
  lineOne: "1234 Main St.",
  // lineTwo is required in this interface
  lineTwo: undefined,
  city: "Springfield",
};

const addressOptional: AddressWithOptionalProperties = {
  lineOne: "1234 Main St.",
  // lineTwo not required!
  city: "Springfield",
};