# Block scoping

// let
function fn () {
  let x = 0
  if (true) {
    let x = 1
  }
}

// const
const a = 1

# Backtick strings

const message = `Hello ${name}`
const str = `hello
  world
  !!!`

# Promises

// making a promise
new Promise((resolve, reject) => {
  if (ok) { resolve(result) }
  else { reject(error) }
})

// using a promise
promise
  .then((result) => { ··· })
  .catch((error) => { ··· })

// promise with finally
promise
  .then((result) => { ··· })
  .catch((error) => { ··· })
  .finally(() => { 
  // ... 
  })

// async-await
async function run () {
  const something = await getSomething()
  const somethingElse = await getSomethingElse(something)
  return [something, somethingElse]
}

# Spread Operator

// objects
const obj = {
  ...objects,
  someProp: true
}

// arrays
const arrs = [
  ...arr1,
  ...arr2,
  'anything else'
]

# Rest Parameter

function fun1(...ars) {
  console.log(args.length);
}

# Fat Arrows

// without args
someFunction(() => {
  ···
})

// with args
anotherFunction('something', (err, data) => {
  ...
})

// implicit return
numbers.map(n => n * 2)

numbers.map(n => ({
  result: n * 2
})