// Request state FIPS data by:
fips.getState('CA'); // State Code
fips.getState('California'); // State Name (Case Insensitive)
fips.getState('06'); // FIPS Code String
fips.getState(6); // FIPS Code String

// Request county FIPS data by:
fips.getCounty('MA', 'Berkshire'); // State Code and County Name
fips.getCounty('Massachusetts', '003'); // State Name and County FIPS Code String
fips.getCounty(25, 3); // State and County FIPS Code Number
fips.getCounty('25003'); // Unified County FIPS Code String

// Get County FIPS Data.
function getCounty(state: State | string | number, county?: string | number): CountyFipsDescriptor | null;

// Get All FIPS County Data for a State.
function getCounties(state: State | string | number): CountyFipsDescriptor[] | null;

// Describes a FIPS state.
interface StateFipsDescriptor {
readonly stateCode: State;
readonly stateName: string;
readonly stateFips: string;
}

// Describes a FIPS county or sub-state administrative boundary.
interface CountyFipsDescriptor {
readonly type: FipsType;
readonly name: string;
readonly fips: string;
readonly stateCode: State;
readonly stateName: string;
readonly stateFips: string;
readonly countyName: string;
readonly countyFips: string;
readonly class: FipsClass;
}

// The type of administrative boundary in question.
enum FipsType {
COUNTY = 'County',
PARISH = 'Parish',
BOROUGH = 'Borough',
DISTRICT = 'District',
CENSUS_AREA = 'Census Area',
MUNICIPALITY = 'Municipality',
TERRITORY = 'Territory',
ISLAND = 'Island',
CITY = 'City',
CITY_BOROUGH = 'City and Borough',
CITY_COUNTY = 'City and County'
}