24.判断昨天今天明天

    let yesterdayStr = '2022-06-28 12:20:45'
    let todayStr = new Date()
    let tomorrowStr = '2022-01-12 10:22:34'
    let dayAfterTomorrow = '2022-01-13 10:23:34'
    /*
    * 判断昨今明
    * */
    function caleDate(dayStr) {
        dayStr = new Date(dayStr).setHours(0, 0, 0, 0);
        let today = new Date().setHours(0, 0, 0, 0);
        let dateObj = {
            '-86400000': '昨天',
            0: '今天',
            86400000: '明天'
        }
        return dateObj[dayStr - today] || '超出昨今明范围';
    }
    console.log(caleDate(yesterdayStr))
       console.log(caleDate(todayStr))
       caleDate('2022-06-27 23:59:45')

判断昨天

let dayTime = new Date('2022-06-28 12:20:45').setHours(0, 0, 0, 0);
let today = new Date().setHours(0, 0, 0, 0);
if(dayTime - today === -86400000){
   return '昨天'
}