// MAPS //

const map = new Map()
//
map.set('key', 'key is a string')
map.set({}, 'key is an object')
map.set(function() {}, 'key is a function')
map.set(true, 'key is a boolean')
map.set(NaN, 'wat')

// OR

const map2 = new Map([
  ['key', 'key is a string'],
  [{}, 'key is an object'],
  [function() {}, 'key is a function'],
  [true, 'key is a boolean'],
  [NaN, 'wat'],
])

// OR

const map3 = new Map()
  .set('key', 'key is a string')
  .set({}, 'key is an object')
  .set(function() {}, 'key is a function')
  .set(true, 'key is a boolean')
  .set(NaN, 'wat')

//MAP METHODS

console.log('map size / length: ', map.size) // 5
console.log('get value associated with a key (key === NaN):', map.get(NaN)) // 'wat'
console.log('check to see if a key exists ("key"):', map.has('key')) // true
console.log('list all keys:', map.keys())
console.log('list all values:', map.values())
console.log('return new iterator object', map.entries())
console.log('delete a key / value pair', map2.delete(NaN)) // true
console.log('Map after key deleted', map2)
console.log('clear map', map2.clear()) // undefined
console.log('map after being cleared', map2)

// ITERATING

// FOR OF

for (var [key, value] of map.entries()) {
  console.log(`key --> ${key},`)
  console.log(`value --> ${value}`)
  console.log('- - - - - - - - - - - -')
}

// FOR EACH

map.forEach((value, key) => {
  console.log(`key --> ${key},`)
  console.log(`value --> ${value}`)
  console.log('- - - - - - - - - - -')
})

// USING ITERATORS

const mapIterator = map.entries()
const mapIterator2 = map.entries()
const mapIterator3 = map[Symbol.iterator]()

console.log(
  'map.entries creates a new iterator object each time its envoked',
  mapIterator === mapIterator2
) //false

console.log('entries is just an iterator', map[Symbol.iterator] === map.entries) //true

console.log(mapIterator.next().value)
console.log(mapIterator.next().value)
console.log(mapIterator.next().value)

console.log(mapIterator3.next().value)
console.log(mapIterator3.next().value)
console.log(mapIterator3.next().value)

// MAPS TO ARRAYS

console.log('keys to array -->', [...map.keys()])
console.log('-------')
console.log('values to array -->', [...map.values()])
console.log('-------')
console.log('map to array -->', [...map])

// MAPPING AND FILTERING

const filteredMap = new Map([...map].filter(([key, value]) => value === 'wat'))
console.log('Filtered Map', filteredMap)

const mappedMap = new Map([...map].map(([key, value]) => [key, `${value}!`]))
console.log('Mapped map', mappedMap)

// SETS //

const set = new Set()

set.add('one')

console.log('check for value', set.has('one'))

set.add(1).add({}).add(function() {}).add(NaN)

// or

const set2 = new Set(['one', 1, {}, function() {}, NaN])

console.log('sets can take arbitrary values', set)

console.log('Sets can easily be converted into an array', Array.from(set))

console.log('set handles NaN correctly', set.has(NaN))

const set3 = new Set().add(1).add(1).add(1).add(1).add(1)
console.log('sets values must be unique', set3.size)

const set4 = new Set([{}, {}, {}, {}, {}])
console.log('objects are different', set4.size)

//ITERATING

for (const x of set) {
  console.log('value: ', x)
}

//MAPS AND FILTERS

const mappedSet = new Set([...set4].map(obj => (obj.key = obj)))
console.log(mappedSet)

// Unions, intersections, and difference

const numSet1 = new Set([1, 2, 3, 4, 5])
const numSet2 = new Set([3, 4, 5, 6, 7])

const union = new Set([...numSet1, ...numSet2])
console.log('unions', union)

const intersection = new Set([...numSet1].filter(x => numSet2.has(x)))
console.log('intersections', intersection)

const diff1 = new Set([...numSet1].filter(x => !numSet2.has(x)))
const diff2 = new Set([...numSet2].filter(x => !numSet1.has(x)))
console.log('difference one', diff1)
console.log('difference two', diff2)