Regex replace last part of url path if condition matches?

Question

I am basically trying to remove the last part of a URL if the URL contains the path /ice/flag/. Example:

Input:

https://test.com/plants/ice/flag/237468372912873

Desired Output:

Because the above URL has /ice/flag/ in its path, I want the last part of the URL to be replaced with redacted.

https://test.com/plants/ice/flag/redacted

However, if the URL did not have /ice/flag (ex: https://test.com/plants/not_ice/flag/237468372912873), it shouldn't be replaced.

What I tried to do is to use the answer mentioned here to change the last part of the path:

var url = 'https://test.com/plants/ice/flag/237468372912873'
url = url.replace(/\/[^\/]*$/, '/redacted')

This works in doing the replacement, but I am unsure how to modify this so that it only matches if /ice/flag is in the path. I tried putting \/ice\/flag in certain parts of the regex to change the behavior to only replace if that is in the string, but nothing has been working. Any tips from those more experienced with regex on how to do this would be greatly appreciated, thank you!

Edit: The URL can be formed in different ways, so there may be other paths before or after /ice/flag/. So all of these are possibilities:

Input:

https://test.com/plants/ice/flag/237468372912873
https://test.com/plants/extra/ice/flag/237468372912873
https://test.com/plants/ice/flag/extra/237468372912873
https://test.com/plants/ice/flag/extra/extra/237468372912873
https://test.com/plants/ice/flag/extra/237468372912873?paramOne=1&paramTwo=2#someHash

Desired Output:

https://test.com/plants/ice/flag/redacted
https://test.com/plants/extra/ice/flag/redacted
https://test.com/plants/ice/flag/extra/redacted
https://test.com/plants/ice/flag/extra/extra/redacted
https://test.com/plants/ice/flag/extra/redacted?paramOne=1&paramTwo=2#someHash

anubhava · Accepted Answer · 2022-09-09 04:41:31Z

2

You may search for this regex:

(\/ice\/flag\/(?:[^?#]*\/)?)[^\/#?]+

and replace it with:

$1redacted

RegEx Demo

RegEx Breakup:

(: Start capture group #1
- \/ice\/flag\/: Match /ice/flag/
- (?:[^?#]*\/)?: Match 0 or more of any char that is not # and ? followed by a / as an optional match
): End capture group #1
[^\/#?]+ Match 1+ of any char that is not / and # and ?

Code:

var arr = [
    'https://test.com/plants/ice/flag/237468372912873', 
    'https://test.com/plants/ice/flag/a/b/237468372912873',
    'https://test.com/a/ice/flag/e/237468372912873?p=2/12#aHash',
    'https://test.com/plants/not_ice/flag/237468372912873'];

var rx = /(\/ice\/flag\/(?:[^?#\n]*\/)?)[^\/#?\n]+/;
var subst = '$1redacted';

arr.forEach(el => console.log(el.replace(rx, subst)));

edited Sep 9, 2022 at 4:41

answered Sep 8, 2022 at 18:23

anubhava

790k67 gold badges603 silver badges671 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

inhwrbp Over a year ago

Sorry, I updated my post at the bottom. I think this is very close to what I was hoping to be able to do, but the issue is that sometimes the path can have stuff before or after the /ice/flag in which case this would not work (ex: https://test.com/plants/ice/flag/hi/237468372912873). Do you think something like this is still possible with regex?

anubhava Over a year ago

Yes I was in the middle of editing my answer based on your recent edit. Please check it now, it should work.

anubhava Over a year ago

Have a look at my updated answer now. btw you didn't need to unmark the answer to get an update from me. I always attend all the comments posted on my answers.

inhwrbp Over a year ago

You're right @anubhava and I apologize. Thanks so much for your help and I really appreciate you detailing out what the pieces of the regex do, I have learned a lot.

anubhava Over a year ago

$1 represents substring that is captured by 1st capture group, which is (\/ice\/flag\/(?:[^?#\n]*\/)?) in this regex.

|

Peter Thoeny · Accepted Answer · 2022-09-09 00:59:06Z

Here is functional code with test input strings based on your requirements:

const input = [
  'https://test.com/plants/ice/flag/237468372912873',
  'https://test.com/plants/extra/ice/flag/237468372912873',
  'https://test.com/plants/ice/flag/extra/237468372912873',
  'https://test.com/plants/ice/flag/extra/extra/237468372912873',
  'https://test.com/plants/ice/flag/extra/237468372912873#someHash',
  'https://test.com/plants/ice/flag/extra/237468372912873?paramOne=1&paramTwo=2#someHash',
  'https://test.com/plants/not_ice/flag/237468372912873'
];
const re = /(\/ice\/flag\/([^\/#?]+\/)*)[^\/#?]+/;

input.forEach(str => {
  console.log('str: ' + str + '\n  => ' + str.replace(re, '$1redacted'));
});

Output:

str: https://test.com/plants/ice/flag/237468372912873
  => https://test.com/plants/ice/flag/redacted
str: https://test.com/plants/extra/ice/flag/237468372912873
  => https://test.com/plants/extra/ice/flag/redacted
str: https://test.com/plants/ice/flag/extra/237468372912873
  => https://test.com/plants/ice/flag/extra/redacted
str: https://test.com/plants/ice/flag/extra/extra/237468372912873
  => https://test.com/plants/ice/flag/extra/extra/redacted
str: https://test.com/plants/ice/flag/extra/237468372912873#someHash
  => https://test.com/plants/ice/flag/extra/redacted#someHash
str: https://test.com/plants/ice/flag/extra/237468372912873?paramOne=1&paramTwo=2#someHash
  => https://test.com/plants/ice/flag/extra/redacted?paramOne=1&paramTwo=2#someHash
str: https://test.com/plants/not_ice/flag/237468372912873
  => https://test.com/plants/not_ice/flag/237468372912873

Regex:

( - capture group start
\/ice\/flag\/ - expect /ice/flag/
([^\/#?]+\/)* - zero or more patterns of chars other than /, #, ?, followed by /
) - capture group end
[^\/#?]+ - discard anything that is not /, #, ? but expect at least one char (this will force stuff after the last /)

Mina · Accepted Answer · 2022-09-08 18:49:15Z

0

You can add a ternary operation condition to check if the url includes /ice/flag by url.includes('/ice/flag'), then replace url.replace(/\/[^\/]*$/, '/redacted') else return the url as it is.

function replace(url) {
  return url.includes('/ice/flag') ? url.replace(/\/[^\/]*$/, '/redacted') : url;
}

console.log(replace("https://test.com/plants/ice/flag/237468372912873"))
console.log(replace("https://test.com/plants/not_ice/flag/237468372912873"));

edited Sep 8, 2022 at 18:49

answered Sep 8, 2022 at 18:26

Mina

17.8k3 gold badges24 silver badges39 bronze badges

Collectives™ on Stack Overflow

Regex replace last part of url path if condition matches?

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related