davidystephenson

type Input <T> = string | number | T

const i: Input<boolean> = false

const x: Input<number[]> = [1, 2, 3]

interface Guest {
  name: string
  email: string
  age: number

davidystephenson

interface Person {
  name: string
  age: number
  email: string
  phone: string
}
interface SpecialPerson extends Person {
  reason: string
}
const tallulah: SpecialPerson = {

davidystephenson

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

const dorothy = {

davidystephenson

<script>
  const review = { message: 'Those were some cute dogs!' }
  const reviewJson = JSON.stringify(review)
  localStorage.setItem('review', reviewJson)
  const localReview = localStorage.getItem('review')
  console.log('localReview', localReview)
  console.log('localReview.message', localReview.message)
  const parsedReview = JSON.parse(localReview)
  console.log('parsedReview.message', parsedReview.message)
</script>

davidystephenson

<script>
  async function upload () {
    const review = { message: 'Those are some cute dogs!' }
    const reviewJson = JSON.stringify(review)
    const init = {
      method: "POST",
      body: reviewJson
    }
    const response = await fetch('https://dog.ceo/api/breeds/image/random', init)
    const data = response.json()

davidystephenson

<img id="image" widt="400"/>
<script>
  async function download () {
    const response = await fetch('https://dog.ceo/api/breeds/image/random')
    const data = await response.json()
    console.log('data', data)
    const image = document.getElementById('image')
    image.src = data.message
  }
  download()

davidystephenson

<script>
  // synchronous (wait)
  console.log('before')

  function sleep(ms) {
    return new Promise((resolve) => {
      setTimeout(() => {
        resolve()
      }, ms)
    })

davidystephenson

// Type definition for wand using tuple
type Wand = [core: string, length: number, material: string]

// Enum for house names
enum House {
  Gryffindor = 'Gryffindor',
  Slytherin = 'Slytherin'
}

// Type for character

davidystephenson

type Message = number | true | 'goodbye'

const message1 = 100 

const message2 = true

const message3 = 'goodbye'

const response: Message[] = [true, 'goodbye', true, 100, 42]
const firstResponse = response[0]

davidystephenson

<script>
  const localCounter = sessionStorage.getItem('counter')
  console.log('savedCounter:', localCounter)
  console.log('typeof savedCounter:', typeof localCounter)

  const counter = Number(localCounter)
  const newCounter = counter + 1
  const newCounterString = String(newCounter)
  sessionStorage.setItem('counter', newCounterString)
</script>