javascript - 如何重启阵列？

Question

我有代码可以提醒当前月份加上过去两个月:

 var cMonth = new Date().getMonth();
 var currentMonth, pastMonth2, pastMonth3 = 0

 var months = [
    "January", 
    "February", 
    "March", 
    "April", 
    "May", 
    "June",
    "July", 
    "August", 
    "September", 
    "October", 
    "November",
    "December"
  ]
    currentMonth = months[cMonth];
    pastMonth2 = months[cMonth - 1];
    pastMonth3 = months[cMonth - 2];

  alert(pastMonth3 + " " + pastMonth2 + " " + currentMonth);

但是，如果月份是一月或二月，我希望它“重新启动数组”并打印十二月和十一月，基本上打印数组的最后一个元素。我能想到的唯一解决方法是使用 if 语句添加验证，但它们无法正常工作，更不用说我觉得这不是一个足够的解决方案(如果不是几个月是一个月中的几天，并且我想打印最后一个，该怎么办？ 12天？)

  if(cMonth == 1){ //prints Undefined Jan, Feb
    currentMonth = months[1]
    pastMonth2 = months[0]
    pastMonth3 = months[11]
  }
  if (cMonth == 0) { //prints Nov, Dec and Jan!
    currentMonth = months[0]
    pastMonth2 = months[11]
    pastMonth3 = months[10]
  } else {
    currentMonth = months[cMonth];
    pastMonth2 = months[cMonth - 1];
    pastMonth3 = months[cMonth - 2];
  }

  alert(pastMonth3 + " " + pastMonth2 + " " + currentMonth);

Answer 1

Date.toLocaleString可用于获取月份名称:

const monthName = m => new Date(0, m).toLocaleString('en-US', { month: 'long' })

var month = new Date().getMonth();

console.log( monthName(month    ) ) // currentMonth 
console.log( monthName(month - 1) ) // pastMonth2
console.log( monthName(month - 2) ) // pastMonth3

console.log( monthName(-2) ) // November
console.log( monthName(13) ) // February