리액트에서 자주 쓰이는 자바스크립트 문법(ES6)

https://www.youtube.com/watch?v=NcI-WJSWdv8 

 

//object shorthand assignment
let name = "mini"
let age = 17

//let person={
//  name = name
//  age = age
//}

let person={
  name,
  age
}

console.log(person)

//Destructuring

let person = {
  name: "mini",
  age: 20
}

// let name = person.name
// let age = person['age']

let { name, age } = person
console.log(name, age) //mini 20


let array = [1,2,3,4]

let [a,b] = array
console.log(a,b) // 1 2

let [a,b...rest] = array
console.log(rest) // [3,4]

//spread
let person = { name: 'mini', age: 12 }

let person2 = { ...person }
let person3 = person

console.log(person2)
//{ name: 'mini', age: 12 }
console.log(person3)
//{ name: 'mini', age: 12 }

//person3은 객체의 주소값만 복사
//person2는 내용은 같지만 새로 생성

console.log(person == person2)//false
console.log(person == person3)//true



//기존값 복사한 후 배열 추가 가능 
let person2 = { ...person, address: "seoul" }
//{ name: 'sori', age: 12, address: "seoul" }

//기존값 복사한 후 수정 가능
let person2 = { ...person, name: "sori" }
//{ name: 'sori', age: 12 }


//배열
let a = [1, 2]
let b = [...a, 3]
console.log(b)
//[1,2,3]

let c = [...a, ...b]
console.log(c)
//[1,2,1,2,3]

//삼항연산자 (ES6는아님)
let person = { name: "mini", age: 17 }

if (person) {
  console.log(person.name)
} else {
  console.log("there is no person")
}
//mini


console.log(person ? person.name : "there is no person")