REGEX: How to remove comments from javascripts, using PHP code

Question

I am combining all my javascriupt into one neat file in order to lower http requests! Im stuck removing the comments /* comments */ and // comments . My level is by far below minification or parsing stuff. I know how to make macaroni strings. Anything more complex than that, you will not find in my computer or kitchen, SO:

QUESTION

meanwhile at combining it to one file, i want to remove all comments.
What is the correct regex for this?

<?php
header('Content-type: text/javascript');    
$offset = 60 * 60 * 24; // Cache for a day
header ('Cache-Control: max-age=' . $offset . ', must-revalidate');
header ('Expires: ' . gmdate ("D, d M Y H:i:s", time() + $offset) . ' GMT');

ob_start("compress");
function compress($buffer) {

# NOT SURE, not all new lines are removed??
# remove tabs, spaces, newlines, etc.
$buffer = str_replace(array("\r\n", "\r", "\t", '  ', '    '), '', $buffer);  

# WORKS !!!
# remove comments / XXXXXXX
$buffer = preg_replace('(// .+)', '', $buffer);

######################################################################## 
# !! STUCK HERE !! OUTPUT FILE LOOKS OK BUT WEBSITE DOESNT LOAD OK IF THIS IS ON
# remove comments / * XXX  (enters etc) XXXX  * /
# $buffer = preg_replace('#/\*(?:.(?!/)|[^\*](?=/)|(?<!\*)/)*\*/#s', '', $buffer);
########################################################################        

return $buffer;
}

include('../file1.js');
include('../file2.js');  
ob_end_flush();
?>

It would be great if it would catch and delete the following:

/* XXXX */

/* 
  XXXX
  XXXX
*/

Thats all! Cant get it to work nomatter what regex i use even with this incredible tool, where i FOUND the right match to be:

RegExp: /\/\*(?:.(?!/)|[^\*](?=/)|(?<!\*)/)*\*\//gs
pattern: \/\*(?:.(?!/)|[^\*](?=/)|(?<!\*)/)*\*\/
flags: gs

http://gskinner.com/RegExr/

Answer 1

Using regular expressions isn't the most efficient way of removing Javascript comments. You need a string parser and minifier. See http://razorsharpcode.blogspot.com/2010/02/lightweight-javascript-and-css.html

If you insist on regex patterns, think about how you would parse this simple code that contains no Javascript comments at all:

var regex=/(ftp|https?):\/\//; alert('hello, world'); return regex;

Notice the double slash before alert() . A stupid parser that uses regular expressions will treat valid Javascript code as comments!

Answer 2

I would like to share a regex (PHP) snippet of code I wrote for myself it is also being used in the YIREO sriptmerge plugin for joomla marked as simple code.. To compress javascript code and remove all comments from it. It also works with mootools It is fast (in comparison to other PHP solutions) and does not damage the JavaScript it self and it resolves lots of comment removal issues.

//--------------------------------------------------------------------------------------------------------- 
//Just started with it!
//Prototype Still working at it when ever I got time by patient please? Tested on 800.000 lines of code!
// Finished it 800.000 lines remove javascript comments without error....16-01-2016
// Its not bullentproof but chances are its gonna work for you...
//----------------------------------------------------------------//-------- //------------------------------------------------------------------------------
//--------------------------------------------------------------------------
//These are 112 lines off code that work together also works with mootools and Joomla and drupal and other cms websites. 
//Tested it on 800.000 lines of code and comments. works fine. 
//This one selects multiple parenthetical like with comments between colons ( abc(/*nn*/('/*xvx*/'))"// testing line") and protect them.
//16-01-2016..! This is the code with the comments in it.!!!!    
//----------------------------------------------------------------//-----------------------------------------
$buffer = preg_replace("/(\*\/\s*)\/\/(?!(\*\/|[^\r\n]*?[\\\\n\\\\r]+\s*\"\s*\+|[^\r\n]*?[\\\\n\\\\r]+\s*\'\s*\+))[^\n\r\;]*?[^\;]\s*[\n\r]/", "$1\n", $buffer);
do {$buffer = preg_replace("/(http(s)?\:)([^\r\n]*?)(\/\/)/", "$1$3qDdXX", $buffer, 1, $count);} while ($count);
do {$buffer = preg_replace("/(^^\s*\/)(\/).*/", "\n", $buffer, 1, $count);} while ($count);
$buffer = preg_replace("/([\r\n]+?\s*|\,\s*|\;\s*|\|\s*|\)\s*|\+\s*|\&\s*|\{\s*|\}\s*|\]\s*|\[\s*|\+\s*|\'\s*|\"\s*|\:\s*|-\s*)((\/)(\/)+)([^\r\n\'\"]*?[nte]'[a-z])*?(?!([^\r\n]*?)([\'\"]|[\\\\]|\*\/|[=]+\s*\";|[=]+\s*\';)).*/", "$1\n", $buffer);
$buffer = preg_replace("/(^^\s*\/\*)(?!([\'\"]))[\s\S]*?(\*\/)/", "\n \n", $buffer);    
$buffer = preg_replace("/(\|\|\s*|=\s*|[\n\r]|\;\s*|\,\s*|\{\s*|\}\s*|\+\s*|\?\s*)((?!([\'\"]))\/\*)(?!(\*\/))[\s\S]*?(\*\/)/", "$1\n", $buffer);
$buffer = preg_replace("/(\;\s*|\,\s*|\{\s*|\}\s*|\+\s*|\?\s*|[\n\r]\s*)((?!([\'\"]))\/\*)(?!(\*\/))[\s\S]*?(\*\/)/", "$1\n", $buffer);
//Remove: ) /* non-empty*//*xxx*/)
do {$buffer = preg_replace('/([^\/\"\'\*a-zA-Z0-9\>])\/\*(?!(\*\/))[^\n\r@]*?\*\/(?=([\/\"\'\\\\\*a-zA-Z0-9\>\s=\)\(\,:;\.\}\{\|\]\[]))/', "$1", $buffer, 1, $count);} while ($count); 
$buffer = preg_replace("/([\;\n\r]\s*)\/\/.*/", "$1\n", $buffer);   
$buffer = preg_replace("/(\/\s\/)([g][\W])/", "ZUQQ$2", $buffer);
$buffer = preg_replace("/\\\\n/", "AQerT", $buffer);
$buffer = preg_replace("/\\\\r/", "BQerT", $buffer);    
////---------------------------------------------------------------------------------------------------------
// Remove all extra new lines after [ and \
$buffer = preg_replace("/([^\*])(\*|[\r\n]|\'|\"|\,|\+|\{|;|\(|\)|\[|\]|\{|\}|\?|[^p|s]:|\&|\%|[^\\\\][a-m-o-u-s-zA-Z]|\||-|=|[0-9])(\s*)(?!([^=\\\\\&\/\"\'\^\*:]))(\/)(\/)+(?!([\r\n\*\+\"]*?([^\r\n]*?\*\/|[^\r\n]*?\"\s*\+|([^\r\n]*?=\";))))([^\n\r]*)([^;\"\'\{\(\}\,]\s*[\\\\\[])(?=([\r\n]+))/", "$1$2$3", $buffer);

// /* followed by (not new line but) ... */ ... /* ... till */
$buffer = preg_replace("/((([\r\n]\s*)(\/\*[^\r\n]*?\*\/(?!([^\n\r]*?\"\s*\+)))([^\n\r]*?\/\*[^\n\r]*?\*\/(?!([^\n\r]*?\"\s*\+))[^\n\r]*?\/\*[^\n\r]*?\*\/(?!([^\n\r]*?\"\s*\+)))+)+(?!([\*]))(?=([^\n\r\/]*?\/\/\/)))/", "$3", $buffer);
// (slash slash) remove everything behinde it not if its followed by */ and /n/r or " + and /n/r
$buffer = preg_replace("/([\r\n]+?\s*)((\/)(\/)+)(?!([^\r\n]*?)([\\\\]|\*\/|[=]+\s*\";|[=]+\s*\';)).*/", "$1\n", $buffer);
// slash slash star between collons protect like: ' //* ' by TDdXX
$buffer = preg_replace("/(\'\s*)(\/\/\*)([^\r\n\*]*?(?!(\*\/))(\'))/", "$1TDdXX$3", $buffer); 
// slash slash star between collons protect like: " //* " by TDdXX
$buffer = preg_replace("/(\"\s*)(\/\/\*)([^\r\n\*]*?(?!(\*\/))(\"))/", "$1TDdXX$3", $buffer); 
// slash slash star between collons protect like: ' //* ' by TDdXX
$buffer = preg_replace("/(\'\s*)(\/\*)([^\r\n\*]*?(?!(\*\/))(\'))/", "$1pDdYX$3", $buffer); 
// slash slash star between collons protect like: " //* " by TDdXX
$buffer = preg_replace("/(\"\s*)(\/\*)([^\r\n\*]*?(?!(\*\/))(\"))/", "$1pDdYX$3", $buffer);
// in regex star slash protect by: ODdPK
$buffer = preg_replace("/(\,\s*)(\*\/\*)(\s*[\}\"\'\;\)])/", "$1RDdPK$3", $buffer); // , */* '
$buffer = preg_replace('/(\n|\r|\+|\&|\=|\|\||\(|[^\)]\:[^\=\,\/\$\\\\\<]|\(|return(?!(\/[a-zA-Z]+))|\!|\,)(?!(\s*\/\/|\n))(\s*\/)([^\]\)\}\*\;\,gi\.]\s*)([^\/\n]*?)(\*\/)/', '$1$4$5$6ODdPK', $buffer); 
//// (slash r) (slash n) protect if followed by " + and new line
$buffer = preg_replace("/[\/][\/]+(AQerTBQerT)(\s*[\"]\s*[\+])/", "WQerT", $buffer);
$buffer = preg_replace("/[\/][\/]+(\*\/AQerTBQerT)(\s*[\"]\s*[\+])/", "YQerT", $buffer);
// Html Text protection!
$buffer = preg_replace("/([\r\n]\s*\/\/)[^\r\n]*?\/\*(?=(\/))[^\r\n]*?([\r\n])/", "$1 */$3", $buffer);
$buffer = preg_replace("/([\)]|[^\/|\\\\|\"])(\/\*)(?=([^\r\n]*?[\\\\][rn]([\\\\][nr])?\s*\"\s*\+\s*(\n|\r)?\s*\"))/", "$1pDdYX", $buffer);
$buffer = preg_replace('/([\"]\s*[\,\+][\r\n]\s*[\"])(\s*\/\/)((\/\/)|(\/))*/', '$1qDdXX', $buffer);
$buffer = preg_replace('/([\"]\s*[\,\+][\r\n]\s*[\"](qDdXX))[\\\\]*(\s*\/\/)*((\/\/)|(\/))*/', '$1', $buffer);
// started by new line slash slash remove all not followed by */ and new line!
$buffer = preg_replace("/([\r\n]\s*)(?=([^\r\n\*\,\:\;a-zA-Z\"]*?))(\/)+(\/)[^\r\n\/][^\r\n\*\,]*?[\*]+(?!([^\r\n]*?(([^\r\n]*?\/|\"\s*\)\s*\;|\"\s*\;|\"\s*\,|\'\s*\)\s*\;|\'\s*\;|\'\s*\,))))[^\r\n]*(?!([\/\r\n]))[^\r\n]*/", "$1", $buffer);
// removes all *.../ achter // leaves the ( // /* staan en */ ) 1 off 2
$buffer = preg_replace("/([\r\n](\/)*[^:\;\,\.\+])(\/\/[^\r\n]*?)(\*)?([^\r\n]+?)(\*)+([^\r\n\*\/])+?(\/[^\*])(?!([^\r\n]*?((\"\s*\)\s*\;|\"\s*\;|\"\s*\,|\'\s*\)\s*\;|\'\s*\;|\'\s*\,))))/", "$1$3$7$8", $buffer);
// removes all /* after // leaves the ( // */ staan ) 2 off 2
do {$buffer = preg_replace("/([\r\n])((\/)*[^:\;\,\.\+])(\/\/[^\r\n]*?)(\*)?([^\r\n]+?)(\/|\*)([^\r\n]*?)(\*)[\r\n]/", "$1", $buffer, 1, $count);} while ($count); 
////---------------------------------------------------------------------------------------------------------
// removes all (/* and */) combinations after // and everything behinde it! but leaves  ///* */ or example. ///*//*/ one times.
$buffer = preg_replace("/(((([\r\n](?=([^:;,\.\+])))(\/)+(\/))(\*))([^\r\n]*?)(\/\*)*([^\r\n])*?(\*\/)(?!([^\r\n]*?((\"\s*\)\s*\;|\"\s*\;|\"\s*\,|\'\s*\)\s*\;|\'\s*\;|\'\s*\,))))(((?=([^:\;\,\.\+])))(\/)*([^\r\n]*?)(\*|\/)?([^\r\n]*?)(\/\*)([^\r\n])*?(\*\/)(?!([^\r\n]*?((\"\s*\)\s*\;|\"\s*\;|\"\s*\,|\'\s*\)\s*\;|\'\s*\;|\'\s*\,)))))*)+[^\r\n]*/", "$2$7$9$10$11$12", $buffer);
// removes /* ... followed by */ repeat even pairs till new line!
$buffer = preg_replace("/(\/\*[\r\n]\s*)(?!([^\/<>;:%~`#@&-_=,\.\$\^\{\[\(\|\)\*\+\?\'\"\a-zA-Z0-9]))(((\/\*)[^\r\n]*?(\*\/)?[^\r\n]*?(\/\*)[^\r\n]*?(\*\/))*((\/\*)[^\r\n]*?(\*\/)))+(?!([^\r\n]*?(\*\/|\/\*)))[^\r\n]*?[\r\n]/", "\n", $buffer);
////---------------------------------------------------------------------------------------------------------
// (Mark) Regex Find all "  Mark with = AwTc  and  CwRc // special cahacers are:  . \ + * ? ^ $ [ ] ( ) { } < > = ! | : " '
$buffer = preg_replace("/(?!([\r\n]))([^a-zA-Z0-9]\+|\?|&|\=|\|\||\!|\(|,|return(?!(\/[a-zA-Z]+))|[^\)]\:)(?!(\s*\/\/|\n|\/\*[^\r\n\*]*?\*\/))(\s*\/([\*\^]?))(?!([\r\n\*\/]|[\*]))(?!(\<\!\-\-))(([^\^\]\)\}\*;,g&\.\"\']?\s*)(?=([\]\)\}\*;,g&\.\/\"\']))?)(([^\r\n]*?)(([\w\W])([\*]?\/\s*)(\})|([^\\\\])([\*]?\/\s*)(\))|([\w\W])([\*]?\/\s*)([i][g]?[\W])|([\w\W])([\*]?\/\s*)([g][i]?[\W])|([\w\W])([\*]?\/\s*)(?=(\,))|([^\\\\]|[\/])([\*]?\/\s*)(;)|([\w\W])([\*]?\/\:\s)(?!([@\]\[\)\(\}\{\.,#%\+-\=`~\*&\^;\:\'\"]))|([^\\\\])([\*]?\/\s*)(\.[^\/])|([^\\\\])([\*]?\/\s*)([\r\n]\s*[;\.,\)\}\]]\s*[^\/]|[\r\n]\s*([i][g]?[\W])|[\r\n]\s*([g][i]?[\W])))|([^\\\\])([\*]?\/\s*)([;\.,\)\}\]]\s*[^\/]|([i][g]?[\W])|([g][i]?[\W])))/", "$2$3$5AwTc$7$8$10$13$15$18$21$24$27$30$33$36$39$44CwRc$16$17$19$20$22$23$25$26$28$31$32$34$35$37$38$40$41$45$46", $buffer);


// Remove all extra new lines after [ and \
$buffer = preg_replace("/([^;\"\'\{\(\}\,\/]\s*[^\/][\\\\\[]\s?)\s*([\r\n]+)/", "$1", $buffer); 
$buffer = preg_replace("/([\|\[])\s*([\|\]])/", "$1$2", $buffer);
// (star slash) or (slash star) 1 sentence! Protect! With pDdYX and ODdPK
do {$buffer = preg_replace('/(AwTc)([^\r\nC]*?)(\/\*)(?=([^\r\n]*?CwRc))/', '$1$2pDdYX', $buffer, 1, $count);} while ($count);
do {$buffer = preg_replace('/(AwTc)([^\r\nC]*?)(\*\/)(?=([^\r\n]*?CwRc))/', '$1$2ODdPK', $buffer, 1, $count);} while ($count);
// (slash slash) 1 sentence! Protect with: qDdXX
do {$buffer = preg_replace('/(AwTc)([^\r\nC]*?)(\/\/)(?=([^\r\n]*?CwRc))/', '$1$2qDdXX', $buffer, 1, $count);} while ($count); 

//---------------------------------------------------------------------------------------------------------
// DEZE WERKT !! multiple parentheticals counting for even ones!
 $buffer = preg_replace("/([^\(\/\"\']\s*)(?!\(\s*function)((\()(?=([^\n\r\)]*?[\'\"]))(?!([^\r\n]*?\"\s*\<[^\r\n]*?\>\s*\"|[^\r\n]*?\"\s*\\\\\s*\"|[^\r\n]*?\"\s*\[[^\r\n]*?\]\s*\"))((?>[^()]+)|(?2))*?\))(?!(\s*\"\s*\;|\s*\'\s*\;|\s*\/|\s*\)|\s*\"|[^\n\r]*?\"\s*\+\s*(\n|\r)?\s*\"))/", "$1 /*Yu*/ $2 /*Zu*/ ", $buffer);

// this one is  SINGLE parentheticals pair.
//     $buffer = preg_replace("/([^\(\/\"\']\s*)((\()(?=([^\n\r\)]*?[\'\"]))(?!(function|\)|[^\r\n]*?\"\s*\+[^\r\n]*?\+\s*\"|[^\r\n]*?\"\s*\<[^\r\n]*?\>\s*\"|[^\r\n]*?\"\s*\\\\\s*\"|[^\r\n]*?\"\s*\[[^\r\n]*?\]\s*\"))([^()]*?\)))(?!(\s*\"\s*\;|\s*\'\s*\;|\s*\/|\s*\)|\s*\"|[^\n\r]*?\"\s*\+\s*(\n|\r)?\s*\"))/", "$1 /*Yu*/ $2 /*Zu*/ ", $buffer); 

// (slash slash) 1 sentence! Protect with: qDdXX
do {$buffer = preg_replace('/(\/\*Yu\*\/)([^\r\n]*?)(\/)(\/)(?=([^\r\n]*?\/\*Zu\*\/))/', '$1$2qDdXX', $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(\/\*Yu\*\/)([^\n\r\'\"]*?[\"\'])([^\n\r\)]*?)(\/\*)([^\n\r\'\"\)]*?[\"\'])([^\n\r]*?\/\*Zu\*\/)/", "$1$2$3pDdYX$5$6", $buffer, 1, $count);} while ($count);
do {$buffer = preg_replace("/(\/\*Yu\*\/)([^\n\r\'\"]*?[\"\'])([^\n\r\)]*?)(\*\/)([^\n\r\'\"\)]*?[\"\'])([^\n\r]*?\/\*Zu\*\/)/", "$1$2$3ODdPK$5$6", $buffer, 1, $count);} while ($count);

//---------------------------------------------------------------------------------------------------------
// (slash slash) 2 sentences! Protect ' and "
do {$buffer = preg_replace("/(=|\+|\(|[a-z]|\,)(\s*)(\")([^\r\n\;\/\'\)\,\]\}\*]*?)(\/)(\/)([^\r\n\;\"\*]*?)(\")/", "$1$2$3$4qDdXX$7$8", $buffer, 1, $count);} while ($count);
do {$buffer = preg_replace("/(=|\+|\(|[a-z]|\,)(\s*)(\')([^\r\n\;\/\'\)\,\]\}\*]*?)(\/)(\/)([^\r\n\*\;\']*?)(\')/", "$1$2$3$4qDdXX$7$8", $buffer, 1, $count);} while ($count); 
// (slash slash) 2 sentences! Protect slash slash between ' and "
do {$buffer = preg_replace("/(\"[^\r\n\;]*?)(\/)(\/)([^\r\n\"\;]*?([\"]\s*(\;|\)|\,)))/", "$1qDdXX$4", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(\'[^\r\n\;]*?)(\/)(\/)([^\r\n\'\;]*?([\']\s*(\;|\)|\,)))/", "$1qDdXX$4", $buffer, 1, $count);} while ($count); 
//---------------------------------------------------------------------------------------------------------
// Remove all slar slash achter \n
$buffer = preg_replace("/([\n\r])([^\n\r\*\,\"\']*?)(?=([^\*\,\:\;a-zA-Z\"]*?))(\/)(\/)+(?=([^\n\r]*?\*\/))([^\n\r]*?(\*\/)).*/", "$1$4$5 $8", $buffer); 
do {$buffer = preg_replace("/([\r\n]\s*)((\/\*(?!(\*\/)))([^\r\n]+?)(\*\/))(?!([^\n\r\/]*?(\/)(\/)+\*))/", "$1$3$6", $buffer, 1, $count);} while ($count);
$buffer = preg_replace("/([\n\r]\/)(\/)+([^\n\r]*?)(\*\/)([^\n\r]*?(\*\/))(?!([^\n\r]*?(\*\/)|[^\n\r]*?(\/\*))).*/", "$1/ $4", $buffer);  
do {$buffer = preg_replace("/([\n\r]\s*\/\*\*\/)([^\n\r=]*?\/\*[^\n\r]*?\*\/)(?=([\n\r]|\/\/))/", "$1", $buffer, 1, $count);} while ($count); 
$buffer = preg_replace("/([\n\r]\s*\/\*\*\/)([^\n\r=]*?)(\/\/.*)/", "$1$2", $buffer); 
// Remove all slash slash achter = '...'; //......
do {$buffer = preg_replace("/(\=\s*)(?=([^\r\n\'\"]*?\'[^\n\r\']*?\'))([^\n\r;]*?[;]\s*)(\/\/[^\r\n][^\r\n]*)[\n\r]/", "$1$3", $buffer, 1, $count);} while ($count);
// protect slash slash '...abc//...abc'!
do {$buffer = preg_replace("/(\=)(\s*\')([^\r\n\'\"]*?)(\/)(\/)([^\r\n]*?[\'])/", "$1$2$3qDdXX$6", $buffer, 1, $count);} while ($count);
//(slash star) or (star slash) : no dubble senteces here! Protect with: pDdYX and ODdPK
do {$buffer = preg_replace("/(\"[^\r\n\;\,\"]*?)(\/)(\*)(?!([YZ]u\*\/))([^\r\n;\,\"]*?)(\")/", "$1pDdYX$5$6", $buffer, 1, $count);} while ($count);   // open
do {$buffer = preg_replace("/([^\"]\"[^\r\n\;\/\,\"]*?)(\s*)(\*)(\/)([^\r\n;\,\"=]*?)(\")/", "$1$2ODdPK$5$6", $buffer, 1, $count);} while ($count); // close
do {$buffer = preg_replace("/(\'[^\r\n\;\,\']*?)(\/)(\*)(?!([YZ]u\*\/))([^\r\n;\,\']*?)(\')/", "$1pDdYX$5$6", $buffer, 1, $count);} while ($count);   // open
do {$buffer = preg_replace("/(\'[^\r\n\;\/\,\']*?)(\s*)(\*)(\/)([^\r\n;\,\']*?)(\')/", "$1$2ODdPK$5$6", $buffer, 1, $count);} while ($count); // close
// protect star slash '...abc*/...abc'!
do {$buffer = preg_replace("/(\'[^\r\n\;\,\']*?)(\*)(\/)([^\r\n;\,\']*?)(\')(?!([^\n\r\+]*?[\']))/", "$1ODdPK$4$5", $buffer, 1, $count);} while ($count); 
// protect star slash '...abc*/...abc'!
do {$buffer = preg_replace("/(\"[^\r\n\;\,\"]*?)(\*)(\/)([^\r\n;\,\"]*?)(\")(?!([^\n\r\+]*?[\"]))/", "$1ODdPK$4$5", $buffer, 1, $count);} while ($count);
 //---------------------------------------------------------------------------------------------------------
//// \n protect
do {$buffer = preg_replace("/(=\s*\"[^\n\r\"]*?)(\/\/)(?=([^\n\r]*?\"\s*;))/", "$1qDdXX", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(=\s*\"[^\n\r\"]*?)(\/\*)(?!([YZ]u\*\/))(?=([^\n\r]*?\"\s*;))/", "$1pDdYX", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(=\s*\"[^\n\r\"]*?)(\*\/)(?=([^\n\r]*?\"\s*;))/", "$1ODdPK", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(=\s*\'[^\n\r\']*?)(\/\/)(?=([^\n\r]*?\'\s*;))/", "$1qDdXX", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(=\s*\'[^\n\r\']*?)(\/\*)(?!([YZ]u\*\/))(?=([^\n\r]*?\'\s*;))/", "$1pDdYX", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(=\s*\'[^\n\r\']*?)(\*\/)(?=([^\n\r]*?\'\s*;))/", "$1ODdPK", $buffer, 1, $count);} while ($count); 
//---------------------------------------------------------------------------------------------------------
// (Slash Slash) alle = " // " and = ' // ' replace by! qDdXX
do {$buffer = preg_replace("/(\=|\()(\s*\")([^\r\n\'\"]*?[\'][^\r\n\'\"]*?)(\/)(\/)([^\r\n\'\"]*?[\'])(\s*\'[^\r\n\'\"]*?)(\/\/|qDdXX)?([^\r\n\'\"]*?[\'][^\r\n\'\"]*?[\"])(?!(\'\)|\s*[\)]?\s*\+|\'))/", "$1$2$3qDdXX$6$7qDdXX$9$10", $buffer, 1, $count);} while ($count); 
do {$buffer = preg_replace("/(\=|\()(\s*\')([^\r\n\'\"]*?[\"][^\r\n\'\"]*?)(\/)(\/)([^\r\n\'\"]*?[\"])(\s*\"[^\r\n\'\"]*?)(\/\/|qDdXX)?([^\r\n\'\"]*?[\"][^\r\n\'\"]*?[\'])(?!(\'\)|\s*[\)]?\s*\+|\'))/", "$1$2$3qDdXX$6$7qDdXX$9$10", $buffer, 1, $count);} while ($count); 
//---------------------------------------------------------------------------------------------------------
// (slash slash) Remove all also , or + not followed by */ and newline
$buffer = preg_replace("/([^\*])(\*|[\r\n]|[^\\\\]\'|[^\\\\]\"|\,|\+|\{|;|\(|\)|\[|\]|\{|\}|\?|[^p|s]:|\&|\%|[^\\\\][a-m-o-u-s-zA-Z]|\||-|=|[0-9])(\s*)(?!([^=\\\\\&\/\"\'\^\*:]))(\/)(\/)+(?!([\r\n\*\+\"]*?([^\r\n]*?\*\/|[^\r\n]*?\"\s*\+|([^\r\n]*?=\";)))).*/", "$1$2$3", $buffer);
// (slash slash star slash) Remove everhing behinde it not followed by */ or new line
$buffer = preg_replace("/(\/\/\*\/)(?!([\r\n\*\+\"]*?([^\r\n]*?\*\/|[^\r\n]*?\"\s*\+|([^\r\n]*?=\";)))).*/", "", $buffer);
// Remove almost all star comments except colon/**/
$buffer = preg_replace("/(?!([^\n\r]*?[\'\"]))(\s*<!--.*-->)(?!(<\/div>))[^\n\r]*?.*/","$2$4", $buffer);
$buffer = preg_replace("/([\n\r][^\n\r\*\,\"\']*?)(?=([^\*\,\:\;a-zA-Z\"]*?))(\/)(\/)+(?!([\r\n\*\+\"]*?([^\r\n]*?\*\/|[^\r\n]*?\"\s*\+|([^\r\n]*?=\";)))).*/", "$1", $buffer);
$buffer = preg_replace("/(?!([^\n\r]*?[\'\"]))(\s*<!--.*-->)(?!(<\/div>))[^\n\r]*?(\*\/)?.*/","", $buffer);
$buffer = preg_replace("/(<!--.*?-->)(?=(\s*<\/div>))/","", $buffer);
//---------------------------------------------------------------------------------------------------------
// Restore all
$buffer = preg_replace("/qDdXX/", "//", $buffer);  // Restore //
$buffer = preg_replace("/pDdYX/", "/*", $buffer);   // Restore 
$buffer = preg_replace("/ODdPK/", "*/", $buffer);   // Restore 
$buffer = preg_replace("/RDdPK/", "*/*", $buffer);   // Restore 
$buffer = preg_replace("/TDdXX/", "//*", $buffer);   // Restore */
$buffer = preg_replace('/WQerT/', '\\\\r\\\\n" +', $buffer);   // Restore \r\n" + 
$buffer = preg_replace('/YQerT/', '//*/\\\\r\\\\n" +', $buffer);   // Restore \r\n" + 
$buffer = preg_replace('/AQerT/', '\\\\n', $buffer);   // Restore \n" 
$buffer = preg_replace('/BQerT/', '\\\\r', $buffer);   // Restore \r"
$buffer = preg_replace("/ZUQQ/", "/ /", $buffer);
$buffer = preg_replace('/\s\/\*Zu\*\/\s/', '', $buffer);   // Restore \n"
$buffer = preg_replace('/\s\/\*Yu\*\/\s/', '', $buffer);   // Restore \n"
////---------------------------------------------------------------------------------------------------------
//// Remove all markings!
$buffer = preg_replace('/(AwTc)/', '', $buffer);  // Start most Regex!
$buffer = preg_replace('/(CwRc)/', '', $buffer);  // End Most regex!
// all \s and [\n\r] repair like they where!
$buffer = preg_replace("/([a-zA-Z0-9]\s?)\s*[\n\r]+(\s*[\)\,&]\s?)(\s*[\r\n]+\s*[\{])/", "$1$2$3", $buffer); 
$buffer = preg_replace("/([a-zA-Z0-9\(]\s?)\s*[\n\r]+(\s*[;\)\,&\+\-a-zA-Z0-9]\s?)(\s*[\{;a-zA-Z0-9\,&\n\r])/", "$1$2$3", $buffer); 
$buffer = preg_replace("/(\(\s?)\s*[\n\r]+(\s*function)/", "$1$2", $buffer);
$buffer = preg_replace("/(=\s*\[[a-zA-Z0-9]\s?)\s*([\r\n]+)/", "$1", $buffer); 
//-----------------------------------------------
$buffer = preg_replace("/([^\*\/\'\"]\s*)(\/\/\s*\*\/)/", "$1", $buffer);
//// Remove all /**/// .... Remove expept /**/ and followed by */ till newline!
$buffer = preg_replace("/(\/\*\*\/)(\/\/(?!([^\n\r]*?\*\/)).*)/", "$1", $buffer);
$buffer = preg_replace("/(\;\/\*\*\/)(?!([^\n\r]*?\*\/)).*/", "", $buffer);
$buffer = preg_replace("/(\/\/\\\\\*[^\n\r\"\'\/]*?[\n\r])/", "\r\n", $buffer);
$buffer = preg_replace("/([\r\n]\s*)(\/\*[^\r\n]*?\*\/(?!([^\r\n]*?\"\s*\+)))/", "$1", $buffer);
//Remove colon /**/
$buffer = preg_replace("/\/\*\*\/\s/", " ", $buffer);
$buffer = preg_replace("/(\=\s*)(?=([^\r\n\'\"]*?\'[^\n\r\'\"]*?\'))([^\n\r\/]*?)(\/\/[^\r\n\"\'][^\r\n]*[\'\"])(\/\*\*\/)[\n\r]/", "$1$3$4\n", $buffer);
$buffer = preg_replace("/(\=\s*)(?=([^\r\n\'\"]*?\"[^\n\r\'\"]*?\"))([^\n\r\/]*?)(\/\/[^\r\n\"\'][^\r\n]*[\'\"])(\/\*\*\/)[\n\r]/", "$1$3$4\n", $buffer);
//Remove colon //
$buffer = preg_replace("/([^\'\"ps\s]\s*)(\:[^\r\n\'\"\[\]]*?\'[^\n\r\'\"]*?\')([^\n\r\/a-zA-Z0-9]*?)(\/\/)[^\r\n\/\'][^\r\n]*/", "$1$2", $buffer);
$buffer = preg_replace("/([^\'\"ps\s]\s*)(\:[^\r\n\'\"\[\]]*?\"[^\n\r\'\"]*?\")([^\n\r\/a-zA-Z0-9]*?)(\/\/)[^\r\n\/\"][^\r\n]*/", "$1$2", $buffer);
$buffer = preg_replace("/(\"[^\n\r\'\"\+]*?\")([^\n\r\/a-zA-Z0-9]*?)(\/\/)(?!(\*|[^\r\n]*?[\\\\n\\\\r]+\s*\"\s*\+|[^\r\n]*?[\\\\n\\\\r]+\s*\'\s*\+))[^\r\n\/\"][^\r\n]*/", "$1$2", $buffer);
//Remove all after ; slah slah+
$buffer = preg_replace("/(;\s*)\/\/(?!([^\n\r]*?\"\s*;)).*/", "$1 \n", $buffer);
//Remove: ) /* non-empty*//*xxx*/)
$buffer = preg_replace('/([\n\r][^\n\r\"]*?)([^\/\"\'\*\>])\/\*(?!(\*\/))[^\n\r\"]*?[^@]\*\//', "$1$2", $buffer);
//Remove // vooraf gegaan door: || | ? | , //
$buffer = preg_replace("/(\|\||[\?]|\,)(\s*)\/\/(?!([^\n\r]*?\*\/|\"|\')).*/", "$1$2", $buffer);
//Remove: [\n\r] after: [ \|\[\;\,\:\=\-\{\}\]\[\?\)\( ]
$buffer = preg_replace("/([\|\[\;\,\:\=\-\{\}\]\[\?\)\(])\s*[\n\r]\s*[\n\r](\s*[\n\r])+/", "$1\n", $buffer);
////---------------------------------------------------------------------------------------------------------
//END Remove comments.    //START Remove all whitespaces    
$buffer = preg_replace('/(--\s+\>)/', 'HwRc', $buffer);  // protect space between: -- >
//-------------------------------------------------------- 
$buffer = preg_replace('/\s+/', ' ', $buffer);
$buffer = preg_replace('/\s*(?:(?=[=\-\+\|%&\*\)\[\]\{\};:\,\.\<\>\!\@\#\^`~]))/', '', $buffer);
$buffer = preg_replace('/(?:(?<=[=\-\+\|%&\*\)\[\]\{\};:\,\.\<\>\?\!\@\#\^`~]))\s*/', '', $buffer);
$buffer = preg_replace('/([^a-zA-Z0-9\s\-=+\|!@#$%^&*()`~\[\]{};:\'",<.>\/?])\s+([^a-zA-Z0-9\s\-=+\|!@#$%^&*()`~\[\]{};:\'",<.>\/?])/', '$1$2', $buffer);
//-------------------------------------------------------
$buffer = preg_replace('/(HwRc)/', '-- >', $buffer);  // Repair space between: -- >
//END Remove all whitespaces

I have just for the fun of it tested this ( var regex=/(ftp|https?):\\/\\//;alert('hello,world'); ) and this /* foo(); // some comment */ /* foo(); // some comment */ and this: "Python's division: 1 // 2" and this //"you dope" example and my compression code those not damage the example above! COMMENT FROM ABOVE:( A stupid parser that uses regular expressions will treat valid JavaScript code as comments!) So Maybe you can also write none stupid parsers with regex???

I am off coarse not a programmer just wanted to make the plugin work like i wanted it to.... Please feel free to leave a comment if you find a problem with this script with valid javascript sentences. And any kind of comments tags combined (or not combined) that it does not solve correctly.. Because I do have a big handycap I do not now any Javascript syntax so I do not know what to expect I just tested it on examples I could find!

Updated needs no more testing 8000.000 lines work fine now.!

Answer 3

I hit a scenario where I load javascript code over the network via xhr, and need to clean the code for eval'ing. I'm using this code:

var cleanCode = function cleanCode(input) {
  // Remove special characters:
  return input.replace(/\/\/[^"'].*?\n/g, '') /* //comments, but ignore a "//" if there is a quote after it */
              .replace(/\n/g, '')             /* Leftover newlines */
              .replace(/\r/g, '');            /* Carriage returns  */
};

I tested using this and the only snag I had was a comment like:

//'key': 'value'

So I had to change that code to the inline comment:

/*'key': 'value'*/ //LEAVE as inline comment, please

This code doesn't get altered:

url += '//' + ...

Feel free to edit/suggest edits to make this more readable.

Answer 4

Pattern for remove comments in JS

$pattern = '/((?:\/\*(?:[^*]|(?:\*+[^*\/]))*\*+\/)|(?:\/\/.*))/';

Pattern for remove comments in CSS

$pattern = '!/\*[^*]*\*+([^/][^*]*\*+)*/!'; 

$str = preg_replace($pattern, '', $str);

I hope above should help someone..