1. (year,month,date)를 입력하면 요일로 반환하기(feat:new Date,getDay)
function getWeekDay(year, month, date) {
const week = ["일", "월", "화", "수", "목", "금", "토"];
const day = new Date(year, month - 1, date).getDay();
console.log(week[day]);
}
2.(new Date(), 몇일?)을 입력하면 입력한 날짜의 "몇일"전의 날짜 받기(feat:new Date, setDate, getDate)
const date = new Date()
function getDateAgo(date,days){
let newDate = new Date(date)
newDate.setDate(date.getDate() - days)
console.log(newDate.getDate())
}
3. (year,month)를 입력하면 month의 마지막 날짜 구하기(feat:new Date)
function getLastDayOfMonth(year,month){
const lastDay = new Date(year,month,0)
console.log(lastDay.getDate())
}
4. 오늘 0시부터 현재까지 몇초가 지났는지 구하기(feat:new Date, Math round)
function getSecondsToday() {
const newDate = new Date();
const year = newDate.getFullYear();
const month = newDate.getMonth();
const date = newDate.getDate();
const ms = newDate - new Date(year, month, date);
console.log(Math.round(ms / 1000));
}
5. 현재부터 내일이 되기까지 몇초 남았는지 구하기(feat:new Date, Math round)
function getSecondsToTomorrow() {
const newDate = new Date();
const year = newDate.getFullYear();
const month = newDate.getMonth();
const date = newDate.getDate();
const tomorrow = new Date(year, month, date + 1);
const ms = tomorrow - newDate;
console.log(Math.round(ms / 1000));
}
1. 1초마다 printNumber(from,to)에 입력한 from에서 to까지의 번호 출력하기
1-1. setInterval 이용하기
function printNumber(from, to) {
let currentNum = from;
let go = setInterval(function run() {
if (currentNum === to) {
clearInterval(go);
}
console.log(currentNum);
currentNum++;
}, 1000);
}
1-2. setTimeout 이용하기
function printNumber(from, to) {
let currentNum = from;
setTimeout(function run() {
if (currentNum < to) {
setTimeout(run, 1000);
}
console.log(currentNum);
currentNum++;
}, 1000);
}