Check if date is a valid one

Question

Following is the scenario   I have a String date and a date format which is different  Ex   date  2016-10-19 dateFormat   DD-MM-YYYY    I need to check if this date is a valid date   I have tried following things  var d   moment  2016-10-19  dateFormat     d isValid   is returning false every time  Does not Moment js parse the date in the given format   Then I tried to format the date in DD-MM-YYYY first and then pass it to Moment js   var d   moment  2016-10-19   format dateFormat   var date   moment d  dateFormat     Now date isValid   is giving me the desired result  but here the Moment js date object is created twice  How can I avoid this  Is there a better solution   FYI I am not allowed to change the dateFormat

User · Answer

I use moment along with new Date to handle cases of undefined data values:

const date = moment(new Date("2016-10-19"));

because of: moment(undefined).isValid() == true

where as the better way: moment(new Date(undefined)).isValid() == false

User · Answer

If the date is valid then the getTime   will always be equal to itself  var date   new Date  2019-12-12    if date getTime   - date getTime       0        console log  Date is valid      else       console log  Date is invalid

User · Answer

console log   moment  2019-09-01    YYYY-MM-DD   isValid        moment  2019-09-01    YYYY-MM-DD   isValid    console log   moment  2019-22-01    YYYY-DD-MM   isValid        moment  2019-22-01    YYYY-DD-MM   isValid    console log   moment  2019-22-22    YYYY-DD-MM   isValid        moment  2019-22-22    YYYY-DD-MM   isValid    console log   moment  undefined    YYYY-DD-MM   isValid        moment  undefined    YYYY-DD-MM   isValid      moment  2019-09-01    YYYY-MM-DD   isValid     true  moment  2019-22-01    YYYY-DD-MM   isValid     true  moment  2019-22-22    YYYY-DD-MM   isValid     false  moment  undefined    YYYY-DD-MM   isValid     false

User · Answer

var date   moment  2016-10-19    DD-MM-YYYY   true    You should add a third argument when invoking moment that enforces strict parsing   Here is the relevant portion of the moment documentation http   momentjs com docs   parsing string-format  It is near the end of the section

User · Answer

Was able to find the solution   Since the date I am getting is in ISO format  only providing date to moment will validate it  no need to pass the dateFormat   var date   moment  2016-10-19      And then date isValid   gives desired result

User · Answer

I just found a really messed up case   moment  Decimal128    YYYY-MM-DD   isValid      true

User · Answer

Try this one  It is not nice but it will work as long as the input is constant format from your date picker   It is badDate coming from your picker in this example  https   jsfiddle net xs8tvox9   var dateFormat    DD-MM-YYYY  var badDate    2016-10-19    var splittedDate   badDate split  -     if  splittedDate length    3      var d   moment splittedDate 2   -  splittedDate 1   -  splittedDate 0   dateFormat     alert d isValid      else       incorrectFormat

User · Answer

How to check if a string is a valid date using Moment  when the date and date format are different Sorry  but did any of the given solutions on this thread actually answer the question that was asked   I have a String date and a date format which is different  Ex   date  2016-10-19 dateFormat   quot DD-MM-YYYY quot   I need to check if this date is a valid date   The following works for me    const date    2016-10-19   const dateFormat    DD-MM-YYYY   const toDateFormat   moment new Date date   format dateFormat   moment toDateFormat  dateFormat  true  isValid        Note   new Date    circumvents the warning that    Moment throws  https   momentjs com guides   warnings js-date       but may not be optimal   But honestly  don t understand why moment isDate   as documented  only accepts an object  Should also support a string in my opinion

User · Answer

Here you go  Working Fidddle    function      var dateFormat    DD-MM-YYYY     alert moment moment  2012-10-19   format dateFormat  dateFormat true  isValid

[javascript] Check if date is a valid one

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