Check whether given string is date value

Question

I need to check whether given string is date or not. Note: Without using any library

I try to use this

if (!isNaN(str) || isNaN(Date.parse(str))) {
    console.log("Not a Date");
} else {
    console.log('It is Date');
}

It works in all scenarios except one, if the given input is Hello 2, it returns It is Date

So, is there any way with which I can appropriately validate my string against Date?

If you know what date format you want to get, you could work with regular expressions. Something like this: https://stackoverflow.com/questions/18758772/how-do-i-validate-a-date-in-this-format-yyyy-mm-dd-using-jquery/18759013 — Maik Lowrey, Apr 09 '21 at 20:00

score 1 · Accepted Answer · answered Apr 09 '21 at 21:15

Seems like your requirement is to validate the date which has year between 1000 - 9999, with validate day and month mapping.

Here is what you should be doing

store a variable by converting it to Date const myDate = new Date(your_date_string);
Then you should write logic to check if the time returned by date is valid number isNaN(myDate.getTime())
Then you should write logic to check if the year is within the range (you require) For eg: myDate.getFullYear() > 9999 || myDate.getFullYear() < 1000
Then you should check if the day and month processed is valid. For that you can get month and date by using myDate.getUTCMonth() & myDate.getUTCDate() accordingly. and check the mapping. Please note UTCMonth and UTCDate is index.
if all the above is valid then the date is valid else not. Somewhat like this

function isValidDate(myDate) {
  const d = new Date(myDate);
  if (Object.prototype.toString.call(d) === '[object Date]') {
    if (isNaN(d.getTime()) || d.getFullYear() > 9999 || d.getFullYear() < 1000 || !(your_date_mapping_logic)) {
      console.log('Invalid Date.');
    } else {
      console.log('Valid Date.');
    }
  }
}

score 0 · Answer 2 · answered Apr 09 '21 at 19:26

0

Try with the below condition

if (isFinite(new Date(str).getTime())) {
    console.log("Not a Date");
} else {
    console.log('It is Date');
}

answered Apr 09 '21 at 19:26

Wazeed

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It works if i give input "Hello 2" but if the string is number like "213213" it says that "It is Date" – Ashutosh Agarwal Apr 09 '21 at 19:31
Yes, the string is successfully getting parsed to date `Tue Jan 01 213213` – Wazeed Apr 09 '21 at 19:36
Are you looking for any specific date format validation? – Wazeed Apr 09 '21 at 19:39
No, the given string could be in any date format, it should validate as Date otherwise not – Ashutosh Agarwal Apr 09 '21 at 19:45

Check whether given string is date value

2 Answers2