Use regular expression with Javascript RegExp constructor

Question

I have a regular expression like this and it works fine using https://regexr.com/

([a-zA-Z0-9-.~%!$&'()*+,;=@]+(/[a-zA-Z0-9-.~%!$&'()+,;=:@]+)/?|(/[a-zA-Z0-9-.~%!$&'()*+,;=:@]+)+/?)(?[a-zA-Z0-9-.~%!$&'()+,;=:@/?])?(#[a-zA-Z0-9-._~%!$&'()+,;=:@/?])?

I would like to use it with RegExp() like below(I just put the above string inside the raw string), but it does not work. Do I need to do any other treatment?

const pattern =String.raw`([a-zA-Z0-9\-._~%!$&'()*+,;=@]+(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)*\/?|(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)+\/?)(\?[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?(\#[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?`;
let re = new RegExp(pattern);
return re.test(somestring)

I also tried enclose the regex with / and / like below and it does not work either. It allows spaces but I don't really allow space.

const re = new RegExp(/([a-zA-Z0-9\-._~%!$&'()*+,;=@]+(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)*\/?|(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)+\/?)(\?[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?(\#[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?/);

Updates: I guess my question should be how do I make sure it matches full text like what I can do test in the website above(attached screenshot below)

Like if I have ``` or space in code, it treat it as valid but not in website above — bunny
– bunny, Commented Apr 29, 2021 at 1:19
Ok, Can you include some sample successful/failed input strings in the question? — Matt
– Matt, Commented Apr 29, 2021 at 1:51
If we can't easily reproduce the issue, it's unlikely to get answers. — Matt
– Matt, Commented Apr 29, 2021 at 1:51

Niles Tanner · Accepted Answer · 2021-04-29 01:57:14Z

2

I think the root of this question is that regexr is matching on the full string rather than just a part. .test() will return true if part of the regex matches. if you want to only return true when matching the on the full string I would suggest using start ^ and end $ delimiters.

const pattern =String.raw`^([a-zA-Z0-9\-._~%!$&'()*+,;=@]+(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)*\/?|(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)+\/?)(\?[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?(\#[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?$`;
let re = new RegExp(pattern);
console.log(re.test('asdf```'))

answered Apr 29, 2021 at 1:57

Niles Tanner

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Matt · Accepted Answer · 2021-04-29 01:56:16Z

1

Match the beginning ^ and end $ of a string to get an exact match, otherwise a substring will be accepted.

const re = new RegExp('^regex$')

On the sample string:

const reStr = `^([a-zA-Z0-9\-._~%!$&'()*+,;=@]+(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)*\/?|(\/[a-zA-Z0-9\-._~%!$&'()*+,;=:@]+)+\/?)(\?[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?(\#[a-zA-Z0-9\-._~%!$&'()*+,;=:@/?]*)?$`

answered Apr 29, 2021 at 1:56

Matt

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