Check date with regular expression

Question

How to use this regular expression to validate the date in this case?

var regex = new RegExp(/[\d-: ]/, 'g');
console.log(regex.test(updated_post_datetime));

The input will be something like that 2011-03-29 12:22somestring It has to return false in that case, but it returns true.

What do you expect `2011-02-29 25:61:73` to return, out of curiosity? — Niet the Dark Absol, Mar 31 '18 at 11:47

score 2 · Accepted Answer · edited Mar 31 '18 at 15:16

2

If you e.g. add ^, + and $ it will work, where

"^"  =  from the beginning of the line
"+"  =  one or more of chosen character
"$"  =  to end of line

var regex = /^[\d-: ]+$/;
console.log(regex.test("2011-03-29 12:22somestring"));
console.log(regex.test("2011-03-29 12:22"));
console.log(regex.test("2011-03-30 12:22"));
console.log(regex.test("2011-04-01 12:22"));
console.log(regex.test("2011-05-19 12:22"));

Do note though, this will return true for e.g. 123 as well, so if you intend to validate that it is really a date, you need something like one of these:

edited Mar 31 '18 at 15:16

Wiktor Stribiżew

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answered Mar 31 '18 at 11:58

Asons

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Thanks. That was what I search for. – Svetlozar Mar 31 '18 at 12:11
Very nice answer! – rtn Mar 31 '18 at 12:14

score 0 · Answer 2 · answered Mar 31 '18 at 12:05

0

An alternative approach:

console.log(!isNaN(Date.parse(updated_post_datetime)));

answered Mar 31 '18 at 12:05

Jos

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10

score 0 · Answer 3 · answered Mar 31 '18 at 12:50

You can try

var regex = new RegExp(/^(?:[12]\d{3})-(?:(0[1-9])|(1[0-2]))-(?:([0-2][1-9])|(3[0-1]))\s+(([01][1-9])|(2[0-3])):([0-5][0-9])|(2[0-3])/, 'g');
console.log(regex.test(updated_post_datetime));

or better try to create a new date for it

var test1 = '2011-03-29 12:22';
console.log(test1 + ' test is: ' + isDate(test1));

var test2 = '2011-02-29 25:61:73';
console.log(test2 + ' test is: ' + isDate(test2));

function isDate(value) {
    if (!value) return false;

    try {
        var dt = new Date(value);
        return dt instanceof Date && !isNaN(dt.valueOf())
    }
    catch (e) {
        return false;
    }
}

because validating date with regular expression alone is not enough

Check date with regular expression

3 Answers3