Detect URL in text without hyperlink and replace normal URL with hyperlink?

Question

I have spent considerable amount of time searching for the solution or trying one, But I did not found one. So my usecase is:

I have a text which can have simple url(with or without http/s) or it can also have hyperlinked url.

What regex should do

It should leave hyperlink url as it is and convert the non hyperlinked url to a hyperlinked URL.

I am learning regex from www.codeburst.com and trying regex at <a href="https://regexr.com">Regexr</a>.

I am learning regex from <a href="www.codeburst.com">www.codeburst.com</a> and trying regex at <a href="https://regexr.com">Regexr</a>.

this regex, but it it not working as expected.

/((?!href).((https?:\/\/)||(www\.)|(mailto:)).+)/gi

I don't see a difference between your source text and your 'Expected Solution' In what way does your regex not do what you want? — MikeB
– MikeB, Commented May 2, 2019 at 9:52
Made changes to the question, now html part is showing correctly. — Sachin Jagtap
– Sachin Jagtap, Commented May 2, 2019 at 9:56
Possible duplicate of What is a good regular expression to match a URL? — Plochie
– Plochie, Commented May 2, 2019 at 9:58
No. Both questions are different. There the questioner wants regex which only pass if url start with http or https. Mine url can start with http, https, www and mailto also. — Sachin Jagtap
– Sachin Jagtap, Commented May 2, 2019 at 10:00

Jan Turoň · Accepted Answer · 2019-05-02 12:02:33Z

You probably need a negative lookbehind (?<!href=") which was added to ECMAScript recently, see this answer
be careful with double || which renders tokend behind this useless (hungry match)
also be careful with .+ which matches everything after (including newline with /s regex option)

I would start with

(?<!href=")(((https?:\/\/)|(www\.)|(mailto:))\S+)

Plochie · Accepted Answer · 2019-05-02 11:30:22Z

(https?:\/\/)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)

The breakout of regex is as follows,

I have checked above regex with following test cases:

Your solution works correctly for urls without hyperlink, but if text is 'with hyperlink url <a href="example.com">ABC</a>', then it gets converted to 'with hyperlink url <a href="<a class="red" href="example.com">https://www.example.com</…>'. For urls inside href, it should keep them as it is.
You can search all the strings matching with above url, and then find the strings not starting with href programmatically.