Drill 23: Key term — Objects and readonly

type Lesson = {
  id: string
  title: string
  readonly slug: string
  published?: boolean
}

const lesson: Lesson = {
  id: '1',
  title: 'Objects and readonly',
  slug: 'objects-and-readonly',
}

const scores: Record<string, number> = {
  quiz: 9,
  challenge: 8,
}

const counts: { [key: string]: number } = {
  lessons: 5,
  minutes: 55,
}