New+Features - ChoDragon9/posts GitHub Wiki
- Any value can be a key, even an object
- Getting an unknown key produces undefined
const map = new Map()
map.set('foo', true)
map.set('bar', false)
map.get('foo') //true
map.has('foo') //true
map.delete('foo')
map.size //2
map.clear() //map.size === 0
const map = new Map([ ['foo', true], ['bar', false]])
const weakMap = new WeakMap()
let obj = {}
weakMap.set(obj, false)
console.log(weakMap.get(obj)) //false
obj = null
// obj in weakMap is garbage-collected
//only get, set, has, delete methods
const set = new Set()
set.add('red')
set.has('red') //true
set.delete('red')
set.has('red') //false
set.add('red')
set.add('green')
set.size //2
set.clear() //set.size === 0
const set = new Set(['red', 'green', 'blue'])
//Chainable
set.add('purple').add('black')
const weakSet = new WeakSet()
let obj = {}
weakSet.add(obj)
weakSet.has(obj) //true
obj = null
// obj in weakSet is garbage-collected
//only add, has, delete methods
Promise๋ ๋๊ธฐ, ์ดํ, ๊ฑฐ๋ถ ์ํ๊ฐ ์์ต๋๋ค.
- ๋๊ธฐ : ์ด๊ธฐ์ํ
- ์ดํ : ์ฑ๊ณต ์ํ, resolve(), Promise.resolve()
- ๊ฑฐ๋ถ : ์คํจ ์ํ, reject(), Promise.reject()
const promise = new Promise((resolve, reject) => {
getData(
response => resolve(response.data),
error => reject(error.message)
)
})
promise
.then(data => console.log(data))
.catch(err => console.error(err))
Promise.all([
getPromise(),
getPromise(),
getPromise()
]) //response all data
.then(data => console.log(data))
.catch(err => console.error(err))
Promise.race([
getPromise(), //1000ms
getPromise(), //500ms
getPromise() //250ms
]) //response of 250ms
.then(data => console.log(data))
.catch(err => console.error(err))