Date的那些事

日期格式化

function dateToString(date) {
  if (date && date instanceof Date) {
    var yyyy = date.getFullYear();
    var mm = date.getMonth() < 9 ? "0" + (date.getMonth() + 1) : (date.getMonth() + 1);
    var dd = date.getDate() < 10 ? "0" + date.getDate() : date.getDate();
    var hh = date.getHours() < 10 ? "0" + date.getHours() : date.getHours();
    var min = date.getMinutes() < 10 ? "0" + date.getMinutes() : date.getMinutes();
    var ss = date.getSeconds() < 10 ? "0" + date.getSeconds() : date.getSeconds();
    return "".concat(yyyy).concat('-').concat(mm).concat('-').concat(dd).concat('-').concat(ss);
  }
  return '';
}

模拟moment插件

/**
    * 格式化时间
    */
myMoment = (date = new Date().getTime()) => {
    this.date = new Date(date)
    return this;
}

/**
    * 输入格式化格式
    */
formate = (formatStr = 'YYYY-MM-DD HH:mm:ss') => {
    const date = this.date
    const year = date.getFullYear()
    const month = date.getMonth() + 1
    const day = date.getDate()
    const week = date.getDay()
    const hour = date.getHours()
    const minute = date.getMinutes()
    const second = date.getSeconds()

    return formatStr.replace(/Y{2,4}|M{1,2}|D{1,2}|d{1,4}|H{1,2}|m{1,2}|s{1,2}/g, (match) => {
        switch (match) {
            case 'YY':
                return String(year).slice(-2)
            case 'YYY':
            case 'YYYY':
                return String(year)
            case 'M':
                return String(month)
            case 'MM':
                return String(month).padStart(2, '0')
            case 'D':
                return String(day)
            case 'DD':
                return String(day).padStart(2, '0')
            case 'd':
                return String(week)
            case 'dd':
                return weeks[week]
            case 'ddd':
                return '周' + weeks[week]
            case 'dddd':
                return '星期' + weeks[week]
            case 'H':
                return String(hour)
            case 'HH':
                return String(hour).padStart(2, '0')
            case 'm':
                return String(minute)
            case 'mm':
                return String(minute).padStart(2, '0')
            case 's':
                return String(second)
            case 'ss':
                return String(second).padStart(2, '0')
            default:
                return match
        }
    })
}

获取当前日期的周边

今天

function showToDay() {
    var Nowdate = new Date();
    M = Number(Nowdate.getMonth()) + 1
    return Nowdate.getFullYear() + "-" + M + "-" + Nowdate.getDate();
}

明天

function showTomorrow() {
    var tom = new Date();
    tom.setDate(tom.getDate() + 1);
    M = Number(tom.getMonth()) + 1
    return tom.getFullYear() + "-" + M + "-" + tom.getDate();
}

本周第一天

function showWeekFirstDay() {
    var Nowdate = new Date();
    var WeekFirstDay = new Date(Nowdate - (Nowdate.getDay() - 1) * 86400000);
    M = Number(WeekFirstDay.getMonth()) + 1
    return WeekFirstDay.getFullYear() + "-" + M + "-" + WeekFirstDay.getDate();
}

本周最后一天

function showWeekLastDay() {
    var Nowdate = new Date();
    var WeekFirstDay = new Date(Nowdate - (Nowdate.getDay() - 1) * 86400000);
    var WeekLastDay = new Date((WeekFirstDay / 1000 + 6 * 86400) * 1000);
    M = Number(WeekLastDay.getMonth()) + 1
    return Nowdate.getFullYear() + "-" + M + "-" + WeekLastDay.getDate();
}

本月第一天

function showMonthFirstDay() {
    var Nowdate = new Date();
    var MonthFirstDay = new Date(Nowdate.getFullYear(), Nowdate.getMonth(), 1);
    M = Number(MonthFirstDay.getMonth()) + 1
    return MonthFirstDay.getFullYear() + "-" + M + "-" + MonthFirstDay.getDate();
}

本月最后一天

function showMonthLastDay() {
    var Nowdate = new Date();
    var MonthNextFirstDay = new Date(Nowdate.getFullYear(), Nowdate.getMonth() + 1, 1);
    var MonthLastDay = new Date(MonthNextFirstDay - 86400000);
    M = Number(MonthLastDay.getMonth()) + 1
    return MonthLastDay.getFullYear() + "-" + M + "-" + MonthLastDay.getDate();
}