fetch
JSON
request / method / GET / POST / PUT / DELETE
POST / PUT / DELETE
PATCH / HEAD
Response / 상태 코드
Content-Type
Ajax
fetch / 비동기 실행
비동기 실행 함수 / setTimeout / setInterval / addEventListener
promise 객체
Promise Chaining
text method / json method
catch
finally
Promise 객체 생성하기 / Promisify
all / race / allSettled / any
async / await
catch문 / finally문
async
async 붙이는 위치