I am trying to validate year using Regex.test in javascript, but no able to figure out why its returning false.
var regEx = new RegExp("^(19|20)[\d]{2,2}$");
regEx.test(inputValue) returns false for input value 1981, 2007
Thanks
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Uh, do you mean "1981, 2007" or "1981" and "2007"?BoltClock– BoltClock2011-07-22 17:28:32 +00:00Commented Jul 22, 2011 at 17:28
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4 Answers
As you're creating a RegExp object using a string expression, you need to double the backslashes so they escape properly. Also [\d]{2,2} can be simplified to \d\d:
var regEx = new RegExp("^(19|20)\\d\\d$");
Or better yet use a regex literal to avoid doubling backslashes:
var regEx = /^(19|20)\d\d$/;
2 Comments
saber tabatabaee yazdi
you save me! man. god, bless you. what is the reason of /[0-9]*/.test("L") return true? in ionic or javascript or ...
BoltClock
@Mote Zart: The single backslash means nothing in a string if it isn't escaped so you're just testing for the literal string
w+. That's why it needs to be doubled.Found the REAL issue:
Change your declaration to remove quotes:
var regEx = new RegExp(/^(19|20)[\d]{2,2}$/);
3 Comments
BoltClock
You may as well just use the regex literal rather than passing it to another
RegExp constructor.
Mrchief
True. Although it was interesting to figure out the issue with the original ask.
Alex Leo
(head banging)This is the correct answer- the single quotes encapsulating the reg expression. I have up-voted all involved as all helpful.
Do you mean
var inputValue = "1981, 2007";
If so, this will fail because the pattern is not matched due to the start string (^) and end string ($) characters.
If you want to capture both years, remove these characters from your pattern and do a global match (with /g)
var regEx = new RegExp(/(?:19|20)\d{2}/g);
var inputValue = "1981, 2007";
var matches = inputValue.match(regEx);
matches will be an array containing all matches.
Comments
I've noticed, for reasons I can't explain, sometimes you have to have two \\ in front of the d.
so try [\\d] and see if that helps.
