ES6-features.js

// var
var num = 7
console.log(num) // 7

// let
let age = 23
console.log(age) // 23

// const
const NAME = 'Jamal Uddin'
console.log(NAME) // Jamal Uddin

// arrow function
const foo = () => {
  return bar
}

const ship = () => foo()

const multiply = (num1, num2) => num1 * num2

// template string
const customer4 = (name, qty) => {
  return `Customer name: ${name}
Product name: tomato
Per unit price: $15
Total price: $${15 * qty}
Thanks for purchasing from us!`
}

console.log(customer4('Jamal', 100))

// Customer name: Jamal
// Product name: tomato
// Per unit price: $15
// Total price: $1500
// Thanks for purchasing from us!

// spread operator
const animals = ['rat', 'cat', 'dog', 'goat']
const fruits = ['apple', 'banana', 'mango']

const mixed = [...animals, ...fruits]
console.log(mixed) // ["rat", "cat", "dog", "goat", "apple", "banana", "mango"]

// Maps
let course = new Map()
course.set('react', {description: 'ui'})
course.set('jest', {description: 'testing'})

console.log(course) // {"react" => {…}, "jest" => {…}}

// Sets
let books = new Set()
books.add = 'Dreams from my father'
books.add = 'Oliver stone'
books.add = 'War and Peace'

console.log(books.size) // 3

// Building Promises
const spacePeople = () => {
  return new Promise((resolve, reject) => {
    const api = 'http://api.open-notify.org/astros.json'
    const request = new XMLHttpRequest()
    request.open('GET', api)
    request.onload = () => {
      if(request.status === 200) {
        resolve(JSON.parse(request.response))
      } else {
        reject(Error(request.statusText))
      }
    }
    request.onerror = (err) => reject(err)
    request.send()
  })
}

spacePeople()
  .then(
    spaceData => console.log(spaceData),
    err => console.error(new Error('cannot load space data'))
  )
)

// async await with fetch
const githubUsersFollowers = async(userName) => {
  try {
    const response = await fetch(`https://api.github.com/users/${userName}/followers`)
    const json = await response.json()
    const followerList = json.map(user => user.login)
    console.log(followerList)
  } catch (err) {
    console.log('data did not load', err)
  }
}

githubUsersFollowers('jamal-pb95')