var timeArray = ['2021-1-09', '2021-02-1', '2021-05-19']
function transTimeTodiffDays(timeArray) {
var temOrigin = +new Date(timeArray[0].replaceAll('-', '/'))
let arrDiffDays = []
timeArray.forEach((a, i, arr) => {
let tem = +new Date(a.replaceAll('-', '/'))
arrDiffDays.push((tem - temOrigin) / 86400000)
})
return arrDiffDays
}
function nextTime(originDay, days = 1) {
if (!originDay) {
return
}
var temOrigin = +new Date(originDay.replaceAll("-", "/"))
var nextTem = temOrigin + days * 86400000
var time = new Date(nextTem).toLocaleDateString().replaceAll("/", "-")
return time
}
console.log(nextTime('2021-1-1', 8))
console