~JavaScript~残り何日？をやりたくて - Qiita

getLimit(limit) {// 2020/10/05 const d = new Date() const nowDate = new Date(d.getFullYear(), d.getMonth(), d.getDate())//今の日付 const year = Number(limit.slice(0, 4)) const month = Number(limit.slice(5, 7)) - 1 const date = Number(limit.slice(8, 10)) const limitDate = new Date(year, month, date)//期限日 const day = 1000 * 60 * 60 * 24//一日のミリ秒の値 return (limitDate - nowDate) / day },