gistfile1.txt

type Input = string[] | number[]

interface Tree {
  branches: number
  species: string
  height: number
  rings: number
}

interface WildTree extends Tree {
  ecosystem: string
}

const wild: WildTree = {
  ecosystem: 'jungle',
  branches: 10,
  species: 'palm',
  rings: 5,
  height: 20
}

type TreeKey = keyof Tree

const oak: Tree = {
  branches: 10,
  species: 'oak',
  height: 50,
  rings: 20
}
const willow: Tree = {
  branches: 100,
  species: 'willow',
  height: 200,
  rings: 70
}

function describeTree (tree: Tree, key: TreeKey) {
  const value = tree[key]
  const message = `The ${key} of this tree is ${value}`
  console.log(message)
}

describeTree(oak, 'species')
describeTree(willow, 'branches')
describeTree(willow, 'height')
describeTree(oak, 'rings')

interface Vehicle {
  speed: number
  seats: number
}

class Car implements Vehicle {
  private position: number
  public speed: number
  public maker: string
  public seats: number

  constructor (speed: number, maker: string, seats: number) {
    this.position = 0
    this.speed = speed
    this.maker = maker
    this.seats = seats
  }

  travel () {
    this.position += this.speed
  }
}

class Racecar extends Car {
  team: string

  constructor(speed: number, maker: string, team: string, seats: number) {
    super(speed, maker, seats)
    this.team = team
  }
}

const myCar = new Car(80, 'scion', 3)
console.log(myCar.speed)
myCar.travel()

function describeVehicle (vehicle: Vehicle) {
  console.log('The speed is:', vehicle.speed)
}
describeVehicle(myCar)