javascrip指定日期加1天

javascrip指定日期加1天，两种写法：
方法一：

		var batch_date_max = ‘2020-01-15’;
        var timestamp = new Date(batch_date_max).getTime();
        var newTime = addDate(timestamp,1);
        var d = new Date(timestamp);
	    d.setDate(d.getDate() + 1);//加一天
	    var m = d.getMonth() + 1;
	    m = m < 10 ? '0' + m : m;
    	var dd = d.getDate();
	    dd = dd < 10 ? '0' + dd : dd;
	    var   newDate = d.getFullYear() + '-' + m + '-' + dd;

或
方法二：

 //日期格式
    Date.prototype.format = function(format) {
    
    
        var date = {
    
    
            "M+": this.getMonth() + 1,
            "d+": this.getDate(),
            "h+": this.getHours(),
            "m+": this.getMinutes(),
            "s+": this.getSeconds(),
            "q+": Math.floor((this.getMonth() + 3) / 3),
            "S+": this.getMilliseconds()
        };
        if (/(y+)/i.test(format)) {
    
    
            format = format.replace(RegExp.$1, (this.getFullYear() + '').substr(4 - RegExp.$1.length));
        }
        for (var k in date) {
    
    
            if (new RegExp("(" + k + ")").test(format)) {
    
    
                format = format.replace(RegExp.$1, RegExp.$1.length == 1
                    ? date[k] : ("00" + date[k]).substr(("" + date[k]).length));
            }
        }
        return format;
    }

			var batch_date_max = $('.batch_date_' + batch_no).val();
            var timestamp = new Date(batch_date_max).getTime();
             timestamp = timestamp / 1000;
             timestamp += 86400;//加一天
             var newDate = new Date(timestamp * 1000).format('yyyy-MM-dd');