Question

我有一个日期数组，我想对其进行排序并仅获取最近的日期

[
  "Mon Jul 16 2018 11:40:28 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:33:46 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:21:36 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:03:42 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:01:05 GMT+0200 (CEST)",
  "Fri Jul 13 2018 08:53:23 GMT+0200 (CEST)",
  "Fri Jul 13 2018 08:52:33 GMT+0200 (CEST)",
  "Thu Jul 12 2018 13:41:59 GMT+0200 (CEST)",
  "Thu Jul 12 2018 13:41:49 GMT+0200 (CEST)",
  "Thu Jul 12 2018 13:41:42 GMT+0200 (CEST)"
]

shouldDisplayDate(date: Date) {
  datesFiltered = [];
  const array = this.users.map(a => a.date)
  for (const date of array) {
    if (!this.datesFiltered.find(d => new Date(d).setHours(0, 0, 0) ===
        new Date(dateString).setHours(0, 0, 0))) {
      this.datesFiltered.push(new Date(dateString).toString())
    }
  }
}

结果：

[
  Mon Jul 16 2018 15:32:50 GMT+0200 (Central European Summer Time),
  Fri Jul 13 2018 09:33:46 GMT+0200 (Central European Summer Time), 
  Thu Jul 12 2018 13:41:59 GMT+0200 (Central European Summer Time) 
]

所以我想检查是否输入Mon Jul 16 2018 11:40:28 GMT+0200 (CEST)是否在对象数组中？

Answer 1

要使用===查看两个日期是否相等，您必须首先在它们上使用.getTime()（请参见this answer for more info）

下面是进行简单日期排序并查找数组中是否存在日期的示例。

要检查日期是否存在于数组中，我首先将字符串日期（我们正在寻找存在的日期）转换为Date obj。然后，我遍历现有日期数组，一次将其转换一次，然后在每个日期上使用Date.getTime()以查看它们是否相等，如果相等，则该函数将返回true。

const dates = [
  "Thu Jul 12 2018 13:41:42 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:03:42 GMT+0200 (CEST)",
  "Thu Jul 12 2018 13:41:59 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:33:46 GMT+0200 (CEST)",
  "Mon Jul 16 2018 11:40:28 GMT+0200 (CEST)",
  "Fri Jul 13 2018 08:53:23 GMT+0200 (CEST)",
  "Fri Jul 13 2018 08:52:33 GMT+0200 (CEST)",
  "Thu Jul 12 2018 13:41:49 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:21:36 GMT+0200 (CEST)",
  "Fri Jul 13 2018 09:01:05 GMT+0200 (CEST)"
];

// simple date sort
let sortedDates = dates.sort(function(a, b) {
  return new Date(b) - new Date(a);
});

console.log(`sorted Dates array is: ${JSON.stringify(sortedDates, null, 2)}`);

console.log(`date exists in array? ${isDateInArray("Mon Jul 16 2018 11:40:28 GMT+0200 (CEST)")}`);

function isDateInArray(dateString) {
  let dateExists = false;
  let date = new Date(dateString);
  dates.forEach(function(arrayDateString) {
      let arrayDate = new Date(arrayDateString);
      if(date.getTime() === arrayDate.getTime()){
        dateExists = true;
      }
  });
  return dateExists;
}

检查日期是否存在于对象数组中

1 个答案: