gistfile1.txt

interface Guest {
  name: string
  age: number
  email: string
  phone: string
  address: string
}
type GuestKey = keyof Guest // 'name' | 'age' | 'email' | 'phone' | 'address'

const dorothy = {
  name: 'Dorothy',
  age: 60,
  email: '[email protected]',
  phone: '555-555-5555',
  address: '123 fake street'
}
console.log('dorothy', dorothy)

function describeGuest (guest: Guest, key: GuestKey) {
  const value = guest[key]
  console.log('The', key, 'for this guest is', value)
}
describeGuest(dorothy, 'age')