gistfile1.txt

type Input <T> = string | number | T

const input1: Input<boolean> = true
const input2: Input<string[]> = true 

type Collection <T> = [T, T, T]

const stringCollection: Collection<string> = ['a', 'b', 'c']
const numberCollection: Collection<number> = ['a', 2, 3]

interface Vehicle <Cargo> {
  position: number
  speed: number
  seats: number
  wheels: number
  cargo: Cargo
}

type DriverlessVehicle = Omit<Vehicle<undefined>, 'seats' | 'wheels'>

const breadVan: Vehicle<{ white: number, brown: number }> = {
  position: 0,
  speed: 50,
  seats: 2,
  wheels: 4,
  cargo: { white: 10, brown: 5 }
}

const passengerVan: Vehicle<string[]> = {
  position: 0,
  speed: 60,
  seats: 20,
  wheels: 4,
  cargo: ['Dorothy', 'Zelda', 'Tallulah']
}

function pilot <Cargo> (vehicle: Vehicle<Cargo>, pilotName: string): Cargo {
  console.log(pilotName, 'is piloting the vehicle')
  return vehicle.cargo
}

type PilotResult = ReturnType<typeof pilot>

const result = pilot(passengerVan, 'David')

const totalPassengers = 1 + result.length