Conversión de fecha y formato de fecha

Ejemplo 1: formato de fecha

/**格式化日期 yyyy-MM-dd hh:ss:mm
 * @Descripttion: 
 * @param {*} param
 * @return {*}
 * @Author: TinaZ
 * @Date: 2021-02-24
 */
function formatDateTime(param) {
    
    
    if(!param) return "";
    var date = new Date(param);
    var y = date.getFullYear();
    var m = date.getMonth() + 1;
    m = m < 10 ? ('0' + m) : m;
    var d = date.getDate();
    d = d < 10 ? ('0' + d) : d;
    var h = date.getHours();
    h = h < 10 ? ('0' + h) : h;
    var minute = date.getMinutes();
    var second = date.getSeconds();
    minute = minute < 10 ? ('0' + minute) : minute;
    second = second < 10 ? ('0' + second) : second;
    return y + '-' + m + '-' + d + ' ' + h + ':' + minute + ':' + second;
};
formatDateTime(1614150811429) // "2021-02-24 15:13:31"
formatDateTime('2021/2/1') // "2021-02-01 00:00:00"

Ejemplo 2: obtener la fecha actual o la fecha alrededor de un día determinado

/**获取日期
* @Descripttion: 
 * @param {*} oparams {day:间隔天数, date:初始日期或时间戳}
 * @return {*}
 * @Author: TinaZ
 * @Date: 2021-02-25
 */
function fnGetDate(oparams) {
    
    
    var day = oparams && oparams.day ? oparams.day : 0;
    var currDate = oparams && oparams.date ? new Date(oparams.date).getTime() : new Date().getTime();
    var date =  new Date(currDate + day*24*60*60*1000);
    var Y = date.getFullYear();
    var M = date.getMonth() + 1; 
    M = M < 10 ? '0' + M : M;
    var D = date.getDate();
    D = D < 10 ? '0' + D : D;
    var H = date.getHours();
    H = H < 10 ? '0' + H : H; 
    var m = date.getMinutes();
    m = m <10 ? '0' + m : m; 
    var s = date.getSeconds();
    s = s < 10 ? '0' + s : s;
    var sDate = Y + '-' + M + '-' + D;
    var sDatetime = Y + '-' + M + '-' + D + ' ' + H + ':' + m + ':' + s;
    return {
    
    date: sDate, datetime: sDatetime};
}

fnGetDate(); // 不传参数获取当前日期 {date: "2021-02-25", datetime: "2021-02-25 13:28:57"} 
fnGetDate({
    
    day: 10, date: '2021/2/25'}) // 10天后的日期 {date: "2021-03-07", datetime: "2021-03-07 00:00:00"}
fnGetDate({
    
    day: -10, date: '2021-02-25'}) // 10天前的日期 {date: "2021-02-15", datetime: "2021-02-15 00:00:00"}