Date.prototype.AddDays = function (days) {
    days = parseInt(days, 10);
    return new Date(this.valueOf() + 1000 * 60 * 60 * 24 * days);
}

例子

var dt = new Date();
console.log(dt.AddDays(-30));
console.log(dt.AddDays(-10));
console.log(dt.AddDays(-1));
console.log(dt.AddDays(0));
console.log(dt.AddDays(1));
console.log(dt.AddDays(10));
console.log(dt.AddDays(30));

结果

2017-09-03T15:01:37.213Z
2017-09-23T15:01:37.213Z
2017-10-02T15:01:37.213Z
2017-10-03T15:01:37.213Z
2017-10-04T15:01:37.213Z
2017-10-13T15:01:37.213Z
2017-11-02T15:01:37.213Z

两种方法:

1:

var a = new Date()
// no_of_days is an integer value
var b = new Date(a.setTime(a.getTime() + no_of_days * 86400000)

2:类似上述方法

var a = new Date()
// no_of_days is an integer value
var b = new Date(a.setDate(a.getDate() + no_of_days)

未来5天:

var date = new Date(),
d = date.getDate(),
m = date.getMonth(),
y = date.getFullYear();


for(i=0; i < 5; i++){
var curdate = new Date(y, m, d+i)
console.log(curdate)
}

最简单的方法是转换为毫秒，然后加上1000*60*60*24毫秒，例如:

var tomorrow = new Date(today.getTime()+1000*60*60*24);

var myDate = new Date();

//add a day to the date
myDate.setDate(myDate.getDate() + 1);

使用这个函数，它解决了我的问题:

    let nextDate = (daysAhead:number) => {
      const today = new Date().toLocaleDateString().split('/')
      const invalidDate = new Date(`${today[2]}/${today[1]}/${Number(today[0])+daysAhead}`)
      if(Number(today[1]) === Number(12)){
        return new Date(`${Number(today[2])+1}/${1}/${1}`)
      }
      if(String(invalidDate) === 'Invalid Date'){
        return new Date(`${today[2]}/${Number(today[1])+1}/${1}`)
      }
        return new Date(`${today[2]}/${Number(today[1])}/${Number(today[0])+daysAhead}`)
    }