I'm working in JavaScript and I need to figure out how to determine a valid date using regular expressions.
The matches will be:
dd-mm-yyyy
dd-mm-yy
Also, no leading zeros should be accepted like:
9-8-2010
10-6-99
How can I write a regular expression to do this?
I came up with this:
function isValidDate(inputDate){
var myRegex = /^(\d{1,2})([\-\/])(\d{1,2})\2(\d{4}|\d{2})$/;
var match = myRegex.exec(inputDate);
if (match != null) {
var auxDay = match[1];
var auxMonth = match[3] - 1;
var auxYear = match[4];
auxYear = auxYear.length < 3 ? (auxYear < 70 ? '20' + auxYear : '19' + auxYear) : auxYear;
var testingDate = new Date(auxYear,auxMonth,auxDay);
return ((auxDay == testingDate.getDate()) && (auxMonth == testingDate.getMonth()) && (auxYear == testingDate.getFullYear()));
} else return false;
}
Works for dd-mm-yyyy, dd-mm-yy, d-m-yyyy and d-m-yy, using - or / as separators
Based on This script
You'd better do a split on - and test all elements. But if you really want to use a regex you can try this one :
/^(?:(?:31-(?:(?:0?[13578])|(1[02]))-(19|20)?\d\d)|(?:(?:29|30)-(?:(?:0?[13-9])|(?:1[0-2]))-(?:19|20)?\d\d)|(?:29-0?2-(?:19|20)(?:(?:[02468][048])|(?:[13579][26])))|(?:(?:(?:0?[1-9])|(?:1\d)|(?:2[0-8]))-(?:(?:0?[1-9])|(?:1[0-2]))-(?:19|20)?\d\d))$/
Explanation:
^ # start of line
(?: # group without capture
# that match 31st of month 1,3,5,7,8,10,12
(?: # group without capture
31 # number 31
- # dash
(?: # group without capture
(?: # group without capture
0? # number 0 optionnal
[13578] # one digit either 1,3,5,7 or 8
) # end group
| # alternative
(1[02]) # 1 followed by 0,1 or 2
) # end group
- # dash
(19|20)? #numbers 19 or 20 optionnal
\d\d # 2 digits from 00 to 99
) # end group
|
(?:(?:29|30)-(?:(?:0?[13-9])|(?:1[0-2]))-(?:19|20)?\d\d)
|
(?:29-0?2-(?:19|20)(?:(?:[02468][048])|(?:[13579][26])))
|
(?:(?:(?:0?[1-9])|(?:1\d)|(?:2[0-8]))-(?:(?:0?[1-9])|(?:1[0-2]))-(?:19|20)?\d\d)
)
$
I've explained the first part, leaving the rest as an exercise.
This match one invalid date : 29-02-1900 but is correct for any date between 01-01-1900 and 31-12-2099
To validate yyyy-mm-dd hh:MM simplistically (24 hr time):
var dateFormat=/^20\d{2}-(0[1-9]|1[0-2])-[0-3]\d\s([0-1][0-9]|2[0-3]):[0-5]\d$/;
var myDate="2017-12-31";
if ( myDate.match(dateFormat)){
console.log('matches');
};
Changing the first term ( 20\d{2} ) to \d{4} will allow any 4-digit year, including 0000 and 9999. Also, this regex forces leading zeroes for month, day, hours, and minutes.
This regex checks for:
This regex doesn't check for:
Step-by-step solution:
function mDateVerify(date) {
function isLeap(y) {
return (y % 400 === 0 || y % 100 !== 0) && (y % 4 === 0);
}
date = date.match(/^(\d{1,2})-(\d{1,2})-(\d+)$/);
if (date === null) {
return false; // if match failed
}
var year = parseInt(date[3], 10),
month = parseInt(date[2], 10),
day = parseInt(date[1], 10);
if (month > 12) {
return false;
}
if (month === 2) { // February
if (isLeap(year)) {
if (day > 29) {
return false;
}
} else {
if (day > 28) {
return false;
}
}
}
if ((month < 8 && month % 2 === 0) || (month >= 8 && month % 2 === 1)) {
if (day > 30) {
return false;
}
}
if (day > 31) {
return false;
}
return true;
}
I got some result to validate for mm/dd/yyyy format
^(((0[1-9]|1[0-2])/(0[1-9]|1[0-9]|2[0-8])|(0[13-9]|1[0-2])/(29|30)|(0[13578]|1[02])/31)/(?!0000)[0-9]{4}|02/29/([0-9]{2}(0[48]|[2468][048]|[13579][26])|(0[48]|[2468][048]|[13579][26])00))$
This variation validates "ddmmyy" without delimiters.
^(?:(?:(?:0[1-9]|1\d|2[0-8])(?:0[1-9]|1[0-2])|(?:29|30)(?:0[13-9]|1[0-2])|31(?:0[13578]|1[02]))\d{2}|2902((?:0[48]|[2468][048]|[13579][26])|00))$
(was tested on debuggex). ... and it validates leap years by two digits in this century anyway.
How about this?
[1-9]{1,2}[-./][1-12]{1}[-./](19|20)[1-99]{1}
I have not tested this. And this does not validate leap years
