Question

我从API获取了一系列日期：

0:{date: "2016-11-17T00:00:00",…}
1:{date: "2016-11-18T00:00:00",…}
2:{date: "2016-11-19T00:00:00",…}
3:{date: "2016-11-21T00:00:00",…}
4:{date: "2016-11-22T00:00:00",…}
5:{date: "2016-11-23T00:00:00",…}

在此示例中，数组缺少此日期：

{date: "2016-11-20T00:00:00",…}

从Javascript或Angular中的日期数组中找到丢失的一天的最佳方法是什么？

因此我以后可以将它作为禁用日传递给日期选择器。

Answer 1

创建一个新数组missingDates []

使用for循环

迭代数组（来自您的API）

for (i = 0; i < array.length; i++){
    var date1 = convert your array item (with index i) to a date
    var date2 = convert your array item (with index i + 1) to a date (keep in mind, index i + 1 cant be > than array.length)

    //calculate diffDays between the 2 dates, if diff is > 1, you have a missing date
    var missingDate = create your missing date (use your date1 variable + 1Day)

    //add misingDate to missingDates[] array
    missingDates.push(missingDate)
}

Answer 2

检查出来：

首先，您可以使用Array.prototype.sort
然后使用Array.prototype.reduce和hash table查找缺少的日期

以下代码段中的演示：

＆＃13;

var array=[
  {date:"2016-11-17T00:00:00"},
  {date:"2016-11-19T00:00:00"},
  {date:"2016-11-18T00:00:00"},
  {date:"2016-11-21T00:00:00"},
  {date:"2016-11-22T00:00:00"},
  {date:"2016-11-23T00:00:00"},
  {date:"2016-11-27T00:00:00"}
];

var result = array.sort(function(a,b){
   return Date.parse(a.date) - Date.parse(b.date);
}).reduce(function(hash){
  return function(p,c){
    var missingDaysNo = (Date.parse(c.date) - hash.prev) / (1000 * 3600 * 24);
    if(hash.prev && missingDaysNo > 1) {
      for(var i=1;i<missingDaysNo;i++)
        p.push(new Date(hash.prev+i*(1000 * 3600 * 24)));
    }
    hash.prev = Date.parse(c.date);
    return p;
  };
}(Object.create(null)),[]);

console.log(result);

＆＃13;

.as-console-wrapper{top:0;max-height:100%!important;}

＆＃13;

Answer 3

如果没有缺少日期，您可以执行方法getMissingDate返回null，如果大于一天的日期之间存在差异，则可以返回Date对象：

＆＃13;

var arr1 = [{date: "2016-11-17T00:00:00"}, {date: "2016-11-18T00:00:00"}, {date: "2016-11-19T00:00:00"}, {date: "2016-11-21T00:00:00"}, {date: "2016-11-22T00:00:00"}, {date: "2016-11-23T00:00:00"}],
    arr2 = [{date: "2016-11-17T00:00:00"}, {date: "2016-11-18T00:00:00"}, {date: "2016-11-19T00:00:00"}, {date: "2016-11-20T00:00:00"}, {date: "2016-11-21T00:00:00"}, {date: "2016-11-22T00:00:00"}, {date: "2016-11-23T00:00:00"}],
    getMissingDate = function(arr) {
      var result = null;
      for (var i = 0, l = arr.length - 1; i < l; i++) {
        var current = new Date(arr[i].date),
            next = new Date(arr[i + 1].date);

        if (1 < Math.ceil(Math.abs(next.getTime() - current.getTime()) / (1000 * 3600 * 24))) {
          result = new Date(current.setDate(current.getDate() + 1));
          break;
        } 
      }

      return result;
    };

console.log('arr1:', getMissingDate(arr1));
console.log('arr2:', getMissingDate(arr2));

＆＃13;

从日期javascript数组中找到失踪的一天

3 个答案: