Regex pattern to match anything between /* and */ in js

Question

I have a string with contents like this:

/*         
    <h1>some text</h1>             
    <div>more stuff $${}{} etc </div>        
*/

I'm trying to get everything between /* and */

Currently:

 string.match(/[^\/\*](.*)[(\*\/)$]/g);

Why doesn't this regex work?

I'm just curious, but why do you have a string with HTML that is commented out with css/js comments ? — adeneo, Mar 18 '14 at 20:40
@adeneo i'm using function.prototype.toString() to create a simple html templating system. — louisinhongkong, Mar 18 '14 at 20:54

score 3 · Accepted Answer · answered Mar 18 '14 at 20:42

Because the . does not match line breaks. Try this instead:

string.match(/\/\*([\s\S]*?)\*\//g);

I also made the * ungreedy otherwise the first /* and last */ would be matched. I.e., the entire input:

/*         
    <h1>some text</h1>             
    <div>more stuff $${}{} etc </div>        
*/
var somethingImportant = 42;
/*         
    ...     
*/

Realize that you will goof up on input like this though:

var s = " ... /* ... ";

Ry- · Answer 2 · 2014-03-18T20:48:08.597

[(\*\/)$]

This tells the regular expression to match any of these characters:

(
*
/
)
$

The first character class is similar.

I don’t really know what you were going for there, but this should work:

/\/\*([\s\S]*?)\*\//

\/\* matches /*; the group matches any number of anything, but as little of it as possible ([\s\S] becase . won’t match newlines in JavaScript and there isn’t an option); and \*\/ matches */.

Enjoy trying this out with '/* strings', /regular expressions/*5, // inline comments /*, and <!-- other inline comments /*.

davidrac · Answer 3 · 2014-03-18T21:06:28.620

0

Try \/\*((?:[^*]|(?:\*(?=[^\/])))*)

The result should be on the first match group.

In languages with zero length look behind (JavaScript does not support this) this should work:

(?<=\/\*)(?:[^*]|(?:\*(?=[^\/])))*

Basically it looks for anything after /* which is either not a * or a * not followed by '/' up until the first */

edited Mar 18 '14 at 21:06

answered Mar 18 '14 at 20:55

davidrac

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thanks for the answer david, but Barts pattern seems to be working alright for now. – louisinhongkong Mar 18 '14 at 21:00
David, FYI: JavaScript does not support `(?<=\/\*)` (look behinds). Your answer suggests you know this, but that might not be known to people reading for an answer to their question in this Q&A. – Bart Kiers Mar 18 '14 at 21:01
Thanks Bart, this is why I wrote the first regex that should work in JavaScript and stated that the second will only work in a language with zero length look behind :) In any case I think the solution you wrote using the ungreedy match is more elegant. – davidrac Mar 18 '14 at 21:04

Regex pattern to match anything between /* and */ in js

3 Answers3