How to check if string is valid date or not?

Question

I want to check if the string is a valid date or not. Date.parse() is not working in this case, because if I pass a string in Date.parse(), it is returning a number.

Sachin Singh · Answer

you haven't use isNaN(), make sure to use it as well.

Sachin Singh · Answer

yes, you are right, then I think regex is the option function checkIfValidDate(str) { const regexExp = /(?:(?:31(\/|-|\.)(?:0?[13578]|1[02]))\1|(?:(?:29|30)(\/|-|\.)(?:0?[13-9]|1[0-2])\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:29(\/|-|\.)0?2\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:(?:0?[1-9])|(?:1[0-2]))\4(?:(?:1[6-9]|[2-9]\d)?\d{2})/gi; return regexExp.test(str); } // Use the function checkIfValidDate( "01-01-2021" ); // true checkIfValidDate( "32-01-2021" ); // false

Sachin Singh · Answer

for javascript use this function IsValidDate(dateString) { return !isNaN( new Date(dateString).getDate()); }

Sachin Singh · Answer

Use TryParse or TryParseExact. If you have to check against a valid date format then use this string format = "ddd dd MMM h:mm tt yyyy" ; DateTime dateTime; if (DateTime.TryParseExact(dateString, format, CultureInfo.InvariantCulture, DateTimeStyles.None, out dateTime)) { Console.WriteLine(dateTime); } else { Console.WriteLine( "Not a date" ); } without format use this DateTime mydate; if (DateTime.TryParse(dateString, out mydate) == true ) { //do any thing with mydate }

Sanjay Makwana · Answer

Even if I use isNaN, it is not working. When you use "abcd" it will give right result, but try with the value I am using, it will not work.

Sanjay Makwana · Answer

This code will return results even if we use string.

Sanjay Makwana · Answer

Thanks for reply. I want this in Javascript.

Basem Alshabani · Answer

Use Tryparse method of DateTime class