【JS】时间工具类

//获取几天前几天后的开始时间
const getStartDate = function (num) {
    var date1 = new Date();
    //今天时间
    var time1 = date1.getFullYear() + "-" + (date1.getMonth() + 1) + "-" + date1.getDate()
    console.log(time1);
    var date2 = new Date(date1);
    date2.setDate(date1.getDate() + num);
    //num是正数表示之后的时间，num负数表示之前的时间，0表示今天
    var time2 = date2.getFullYear() + "-" + getPadFmt(date2.getMonth() + 1) + "-" + getPadFmt(date2.getDate()) + " 23:59:59";

    console.log(time2);
    return time2;
}

//获取几天前几天后的结束时间
const getEndDate = function (num) {
    var date1 = new Date();
    //今天时间
    var date2 = new Date(date1);
    date2.setDate(date1.getDate() + num);
    //num是正数表示之后的时间，num负数表示之前的时间，0表示今天
    var time2 = date2.getFullYear() + "-" + getPadFmt(date2.getMonth() + 1) + "-" + getPadFmt(date2.getDate()) + " 23:59:59";
    console.log(time2);
    return time2;
}

//获取几年前几年后的时间
const getAddyearEndDate = function (num) {
    var date = new Date();
    //今天时间
    date.setFullYear(date.getFullYear() + num);
    //num是正数表示之后的时间，num负数表示之前的时间，0表示今天
    var time2 = date.getFullYear() + "-" + getPadFmt(date.getMonth() + 1) + "-" + getPadFmt(date.getDate()) + " 23:59:59";
    console.log(time2);
    return time2;
}


//获取几个月前几个月后的时间
const getAddMonthDate = function (num) {
    var date = new Date();
    //今天时间
    date.setMonth(date.getMonth() + num);
    //num是正数表示之后的时间，num负数表示之前的时间，0表示今天
    var time2 = date.getFullYear() + "-" + getPadFmt(date.getMonth() + 1) + "-" + getPadFmt(date.getDate()) + " 00:00:00";
    console.log(time2);
    return time2;
}


const getPadFmt = function (num) {
   if(num < 10){
       return "0"+num;
   }
    return num;
}


//字符串转时间
const stringToDate = function (dateStr, separator) {
    if (!separator) {
        separator = " ";
    }
    let dateArr = dateStr.split(separator)[0].split("-");
    let timeArr = dateStr.split(separator)[1].split(":");
    let year = parseInt(dateArr[0]);
    let month;
    //处理月份为04这样的情况
    if (dateArr[1].indexOf("0") == 0) {
        month = parseInt(dateArr[1].substring(1));
    } else {
        month = parseInt(dateArr[1]);
    }
    let day = parseInt(dateArr[2]);
    let hour;
    let minutes;
    let seconds;
    if (timeArr[0].indexOf("0") == 0) {
        hour = parseInt(timeArr[0].substring(1));
    } else {
        hour = parseInt(timeArr[0]);
    }

    if (timeArr[1].indexOf("0") == 0) {
        minutes = parseInt(timeArr[1].substring(1));
    } else {
        minutes = parseInt(timeArr[1]);
    }

    if (timeArr[2].indexOf("0") == 0) {
        seconds = parseInt(timeArr[2].substring(1));
    } else {
        seconds = parseInt(timeArr[2]);
    }

    let date = new Date(year, month - 1, day, hour, minutes, seconds);
    return date;
}



//时间格式转字符串格式
const dateToString = function (date) {
    let year = date.getFullYear();
    let month = (date.getMonth() + 1).toString();
    let day = (date.getDate()).toString();
    let hours = (date.getHours()).toString();
    let minutes = (date.getMinutes()).toString();
    let seconds = (date.getSeconds()).toString();
    if (month.length == 1) {
        month = "0" + month;
    }
    if (day.length == 1) {
        day = "0" + day;
    }

    if (hours.length == 1) {
        hours = "0" + hours;
    }
    if (minutes.length == 1) {
        minutes = "0" + minutes;
    }
    if (seconds.length == 1) {
        seconds = "0" + seconds;
    }
    let dateTime = year + "-" + month + "-" + day + " " + hours + ":" + minutes + ":" + seconds;
    return dateTime;
}