Regex for matching multiple forward slashes in URL

Question

I need a regular expression for replacing multiple forward slashes in a URL with a single forward slash, excluding the ones following the colon

e.g. http://link.com//whatever/// would become http://link.com/whatever/

score 38 · Answer 1 · edited Jun 24 '14 at 08:24

38

I think this should work: /[^:](\/+)/ or /[^:](\/\/+)/ if you want only multiples.

It wont match leading // but it looks like you're not looking for that.

To replace:

"http://test//a/b//d".replace(/([^:]\/)\/+/g, "$1") // -->  http://test/a/b/d

Working Demo

edited Jun 24 '14 at 08:24

Milind Anantwar

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answered Mar 26 '13 at 13:23

Halcyon

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When i try to replace the matches with a single forward slash he first one returns http:/link.co/whateve/ and the second one ttp://link.co/whateve/ . For some reason it removes the first preceding character. – geochr Mar 26 '13 at 13:27
Oh, you want to _replace_ them, and not just _match_ them? That's an important difference. – Halcyon Mar 26 '13 at 13:35
@JeffShaver no : it remove some chars – Denys Séguret Mar 26 '13 at 13:35
@dystroy yeah, just saw that – Jeff Shaver Mar 26 '13 at 13:36
2

In your regular expression you don't need the second match group: `/([^:])\/\/+/g` is enough – Halcyon Mar 26 '13 at 13:41
yourString.replace(/(https?:\/\/)|(\/)+/g, "$1$2"); – Burak Tasci Feb 24 '17 at 13:53
You might instead use a positive lookbehind to only match the `//` and not the prepending character: `(?<=[^:])(\/\/+)` – Mentor Mar 15 '22 at 09:21

score 2 · Accepted Answer · answered Mar 26 '13 at 14:30

As you already accepted an answer. To show some more extend of matching and controlling the matches, this might help you in the future:

var url = 'http://link.com//whatever///';
var set = url.match(/([^:]\/{2,3})/g); // Match (NOT ":") followed by (2 OR 3 "/")

for (var str in set) {
    // Modify the data you have
    var replace_with = set[str].substr(0, 1) + '/';

    // Replace the match
    url = url.replace(set[str], replace_with);
}

console.log(url);

Will output:

http://link.com/whatever/

Doublets won't matter in your situation. If you have this string:

var url = 'http://link.com//om/om/om/om/om///';

Your set array will contain multiple m//. A bit redundant, as the loop will see that variable a few times. The nice thing is that String.replace() replaces nothing if it finds nothing, so no harm done.

What you could do is strip out the duplicates from set first, but that would almost require the same amount of resources as just letting the for-loop go over them.

Good luck!

score 0 · Answer 3 · answered Mar 26 '13 at 13:43

0

result = subject.replace(/(?<!http:)\/*\//g, "/");

or (for http, https, ftp and ftps)

result = subject.replace(/(?<!(?:ht|f)tps?:)\/*\//g, "/");

answered Mar 26 '13 at 13:43

Ahmed KRAIEM

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The original question did not ask anything about replacing the scheme. This answer is not relevant. – codeadventurer Oct 16 '17 at 16:31
@codeadventurer, this regular expression doesn't replace the scheme. This answer is relevant. – Andrew Dibble Mar 10 '20 at 14:34

score 0 · Answer 4 · answered Jun 28 '22 at 16:24

The original accepted answer does a sufficient job at replacing, but not for matching. And the currently accepted answer matches the character before duplicate slashes, also not good for matching.

Using a negative lookbehind to exclude the protocol from the match (?<!:), and a curly bracket quantifier to match 2 to infinite slashes \/{2,} does the job to both match and replace.

(?<!:)\/{2,}

let str = 'https://test.example.com:8080//this/is//an/exmaple///';
document.write('Original: ' + str + '<br><br>');
document.write('Matches: ' + str.match(/(?<!:)\/{2,}/g) + '<br><br>');
document.write('Replaced: ' + str.replace(/(?<!:)\/{2,}/g, '/'));

Regex for matching multiple forward slashes in URL

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