我想知道JS中有效日期对象和无效日期对象之间的区别,但无法弄清楚:

var d = new Date("foo");
console.log(d.toString()); // shows 'Invalid Date'
console.log(typeof d); // shows 'object'
console.log(d instanceof Date); // shows 'true'

编写isValidDate函数有什么想法吗?

Ash建议使用Date.parse来解析日期字符串,这提供了一种权威的方法来检查日期字符串是否有效。如果可能的话,我更希望我的API接受Date实例,并能够检查/断言它是否有效。Borgar的解决方案做到了这一点,但我需要在浏览器上进行测试。我还想知道是否有更优雅的方式。Ash让我考虑不让我的API接受Date实例,这是最容易验证的。Borgar建议测试Date实例,然后测试Date的时间值。如果日期无效,则时间值为NaN。我用ECMA-262检查了一下,这种行为符合标准,这正是我所要的。


当前回答

我使用以下代码验证年、月和日期的值。

function createDate(year, month, _date) {
  var d = new Date(year, month, _date);
  if (d.getFullYear() != year 
    || d.getMonth() != month
    || d.getDate() != _date) {
    throw "invalid date";
  }
  return d;
}

有关详细信息,请参阅javascript中的检查日期

其他回答

此函数以字符分隔的数字格式验证字符串日期,例如dd/mm/yyyy、mm/dd/yyyy

/*
Param  : 
1)the date in string data type 
2)[optional - string - default is "/"] the date delimiter, most likely "/" or "-"
3)[optional - int - default is 0] the position of the day component when the date string is broken up via the String.split function (into arrays)
4)[optional - int - default is 1] the position of the month component when the date string is broken up via the String.split function (into arrays)
5)[optional - int - default is 2] the position of the year component when the date string is broken up via the String.split function (into arrays)

Return : a javascript date is returned if the params are OK else null
*/
function IsValidDate(strDate, strDelimiter, iDayPosInArray, iMonthPosInArray, iYearPosInArray) {
    var strDateArr; //a string array to hold constituents day, month, and year components
    var dtDate; //our internal converted date
    var iDay, iMonth, iYear;


    //sanity check 
    //no integer checks are performed on day, month, and year tokens as parsing them below will result in NaN if they're invalid
    if (null == strDate || typeof strDate != "string")
        return null;

    //defaults
    strDelimiter = strDelimiter || "/";
    iDayPosInArray = undefined == iDayPosInArray ? 0 : iDayPosInArray;
    iMonthPosInArray = undefined == iMonthPosInArray ? 1 : iMonthPosInArray;
    iYearPosInArray = undefined == iYearPosInArray ? 2 : iYearPosInArray;

    strDateArr = strDate.split(strDelimiter);

    iDay = parseInt(strDateArr[iDayPosInArray],10);
    iMonth = parseInt(strDateArr[iMonthPosInArray],10) - 1; // Note: months are 0-based
    iYear = parseInt(strDateArr[iYearPosInArray],10);

    dtDate = new Date(
        iYear,
        iMonth, // Note: months are 0-based
        iDay);

    return (!isNaN(dtDate) && dtDate.getFullYear() == iYear && dtDate.getMonth() == iMonth && dtDate.getDate() == iDay) ? dtDate : null; // Note: months are 0-based
}

示例调用:

var strDate="18-01-1971";

if (null == IsValidDate(strDate)) {

  alert("invalid date");
}

尝试以下操作:

if (!('null' === JSON.stringify(new Date('wrong date')))) console.log('correct');
else console.log('wrong');

我很少推荐没有的图书馆。但考虑到目前为止的大量答案,似乎值得指出的是,流行的库“date fns”有一个函数isValid。以下文件摘自其网站:

isValid argument Before v2.0.0 v2.0.0 onward
new Date() true true
new Date('2016-01-01') true true
new Date('') false false
new Date(1488370835081) true true
new Date(NaN) false false
'2016-01-01' TypeError false
'' TypeError false
1488370835081 TypeError true
NaN TypeError false
// check whether date is valid
var t = new Date('2011-07-07T11:20:00.000+00:00x');
valid = !isNaN(t.valueOf());

基于顶级答案的就绪功能:

  /**
   * Check if date exists and is valid.
   *
   * @param {String} dateString Date in YYYY-mm-dd format.
   */
  function isValidDate(dateString) {
  var isValid = false;
  var date;

  date =
    new Date(
      dateString);

  if (
    Object.prototype.toString.call(
      date) === "[object Date]") {

    if (isNaN(date.getTime())) {

      // Date is unreal.

    } else {
      // Date is real if month and day match each other in date and string (otherwise may be shifted):
      isValid =
        date.getUTCMonth() + 1 === dateString.split("-")[1] * 1 &&
        date.getUTCDate() === dateString.split("-")[2] * 1;
    }
  } else {
    // It's not a date.
  }

  return isValid;
}