How to compress and merge js in php

require_once('jsmin.php');

$files = glob("js/*.js");

$js = "";

foreach($files as $file) {

  $js .= JSMin::minify(file_get_contents($file));

}

file_put_contents("combined.js", $js);

echo "success";

<?php

/**

 * jsmin.php - PHP implementation of Douglas Crockford's JSMin.

 *

 * This is pretty much a direct port of jsmin.c to PHP with just a few

 * PHP-specific performance tweaks. Also, whereas jsmin.c reads from stdin and

 * outputs to stdout, this library accepts a string as input and returns another

 * string as output.

 *

 * PHP 5 or higher is required.

 *

 * Permission is hereby granted to use this version of the library under the

 * same terms as jsmin.c, which has the following license:

 *

 * --

 * Copyright (c) 2002 Douglas Crockford (www.crockford.com)

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy of

 * this software and associated documentation files (the "Software"), to deal in

 * the Software without restriction, including without limitation the rights to

 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

 * of the Software, and to permit persons to whom the Software is furnished to do

 * so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in all

 * copies or substantial portions of the Software.

 *

 * The Software shall be used for Good, not Evil.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 * --

 *

 * @package JSMin

 * @author Ryan Grove <ryan@wonko.com>

 * @copyright 2002 Douglas Crockford <douglas@crockford.com> (jsmin.c)

 * @copyright 2008 Ryan Grove <ryan@wonko.com> (PHP port)

 * @copyright 2012 Adam Goforth <aag@adamgoforth.com> (Updates)

 * @license http://opensource.org/licenses/mit-license.php MIT License

 * @version 1.1.2 (2012-05-01)

 * @link https://github.com/rgrove/jsmin-php

 */

class JSMin {

 const ORD_LF      = 10;

 const ORD_SPACE     = 32;

 const ACTION_KEEP_A   = 1;

 const ACTION_DELETE_A  = 2;

 const ACTION_DELETE_A_B = 3;

 protected $a      = '';

 protected $b      = '';

 protected $input    = '';

 protected $inputIndex = 0;

 protected $inputLength = 0;

 protected $lookAhead  = null;

 protected $output   = '';

 // -- Public Static Methods --------------------------------------------------

 /**

  * Minify Javascript

  *

  * @uses __construct()

  * @uses min()

  * @param string $js Javascript to be minified

  * @return string

  */

 public static function minify($js) {

  $jsmin = new JSMin($js);

  return $jsmin->min();

 }

 // -- Public Instance Methods ------------------------------------------------

 /**

  * Constructor

  *

  * @param string $input Javascript to be minified

  */

 public function __construct($input) {

  $this->input    = str_replace("\r\n", "\n", $input);

  $this->inputLength = strlen($this->input);

 }

 // -- Protected Instance Methods ---------------------------------------------

 /**

  * Action -- do something! What to do is determined by the $command argument.

  *

  * action treats a string as a single character. Wow!

  * action recognizes a regular expression if it is preceded by ( or , or =.

  *

  * @uses next()

  * @uses get()

  * @throws JSMinException If parser errors are found:

  *     - Unterminated string literal

  *     - Unterminated regular expression set in regex literal

  *     - Unterminated regular expression literal

  * @param int $command One of class constants:

  *   ACTION_KEEP_A   Output A. Copy B to A. Get the next B.

  *   ACTION_DELETE_A  Copy B to A. Get the next B. (Delete A).

  *   ACTION_DELETE_A_B Get the next B. (Delete B).

 */

 protected function action($command) {

  switch($command) {

   case self::ACTION_KEEP_A:

    $this->output .= $this->a;

   case self::ACTION_DELETE_A:

    $this->a = $this->b;

    if ($this->a === "'" || $this->a === '"') {

     for (;;) {

      $this->output .= $this->a;

      $this->a    = $this->get();

      if ($this->a === $this->b) {

       break;

      }

      if (ord($this->a) <= self::ORD_LF) {

       throw new JSMinException('Unterminated string literal.');

      }

      if ($this->a === '\\') {

       $this->output .= $this->a;

       $this->a    = $this->get();

      }

     }

    }

   case self::ACTION_DELETE_A_B:

    $this->b = $this->next();

    if ($this->b === '/' && (

      $this->a === '(' || $this->a === ',' || $this->a === '=' ||

      $this->a === ':' || $this->a === '[' || $this->a === '!' ||

      $this->a === '&' || $this->a === '|' || $this->a === '?' ||

      $this->a === '{' || $this->a === '}' || $this->a === ';' ||

      $this->a === "\n" )) {

     $this->output .= $this->a . $this->b;

     for (;;) {

      $this->a = $this->get();

      if ($this->a === '[') {

       /*

        inside a regex [...] set, which MAY contain a '/' itself. Example: mootools Form.Validator near line 460:

         return Form.Validator.getValidator('IsEmpty').test(element) || (/^(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]\.?){0,63}[a-z0-9!#$%&'*+/=?^_`{|}~-]@(?:(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)*[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\])$/i).test(element.get('value'));

       */

       for (;;) {

        $this->output .= $this->a;

        $this->a = $this->get();

        if ($this->a === ']') {

          break;

        } elseif ($this->a === '\\') {

         $this->output .= $this->a;

         $this->a    = $this->get();

        } elseif (ord($this->a) <= self::ORD_LF) {

         throw new JSMinException('Unterminated regular expression set in regex literal.');

        }

       }

      } elseif ($this->a === '/') {

       break;

      } elseif ($this->a === '\\') {

       $this->output .= $this->a;

       $this->a    = $this->get();

      } elseif (ord($this->a) <= self::ORD_LF) {

       throw new JSMinException('Unterminated regular expression literal.');

      }

      $this->output .= $this->a;

     }

     $this->b = $this->next();

    }

  }

 }

 /**

  * Get next char. Convert ctrl char to space.

  *

  * @return string|null

  */

 protected function get() {

  $c = $this->lookAhead;

  $this->lookAhead = null;

  if ($c === null) {

   if ($this->inputIndex < $this->inputLength) {

    $c = substr($this->input, $this->inputIndex, 1);

    $this->inputIndex += 1;

   } else {

    $c = null;

   }

  }

  if ($c === "\r") {

   return "\n";

  }

  if ($c === null || $c === "\n" || ord($c) >= self::ORD_SPACE) {

   return $c;

  }

  return ' ';

 }

 /**

  * Is $c a letter, digit, underscore, dollar sign, or non-ASCII character.

  *

  * @return bool

  */

 protected function isAlphaNum($c) {

  return ord($c) > 126 || $c === '\\' || preg_match('/^[\w\$]$/', $c) === 1;

 }

 /**

  * Perform minification, return result

  *

  * @uses action()

  * @uses isAlphaNum()

  * @uses get()

  * @uses peek()

  * @return string

  */

 protected function min() {

  if (0 == strncmp($this->peek(), "\xef", 1)) {

    $this->get();

    $this->get();

    $this->get();

  }

  $this->a = "\n";

  $this->action(self::ACTION_DELETE_A_B);

  while ($this->a !== null) {

   switch ($this->a) {

    case ' ':

     if ($this->isAlphaNum($this->b)) {

      $this->action(self::ACTION_KEEP_A);

     } else {

      $this->action(self::ACTION_DELETE_A);

     }

     break;

    case "\n":

     switch ($this->b) {

      case '{':

      case '[':

      case '(':

      case '+':

      case '-':

      case '!':

      case '~':

       $this->action(self::ACTION_KEEP_A);

       break;

      case ' ':

       $this->action(self::ACTION_DELETE_A_B);

       break;

      default:

       if ($this->isAlphaNum($this->b)) {

        $this->action(self::ACTION_KEEP_A);

       }

       else {

        $this->action(self::ACTION_DELETE_A);

       }

     }

     break;

    default:

     switch ($this->b) {

      case ' ':

       if ($this->isAlphaNum($this->a)) {

        $this->action(self::ACTION_KEEP_A);

        break;

       }

       $this->action(self::ACTION_DELETE_A_B);

       break;

      case "\n":

       switch ($this->a) {

        case '}':

        case ']':

        case ')':

        case '+':

        case '-':

        case '"':

        case "'":

         $this->action(self::ACTION_KEEP_A);

         break;

        default:

         if ($this->isAlphaNum($this->a)) {

          $this->action(self::ACTION_KEEP_A);

         }

         else {

          $this->action(self::ACTION_DELETE_A_B);

         }

       }

       break;

      default:

       $this->action(self::ACTION_KEEP_A);

       break;

     }

   }

  }

  return $this->output;

 }

 /**

  * Get the next character, skipping over comments. peek() is used to see

  * if a '/' is followed by a '/' or '*'.

  *

  * @uses get()

  * @uses peek()

  * @throws JSMinException On unterminated comment.

  * @return string

  */

 protected function next() {

  $c = $this->get();

  if ($c === '/') {

   switch($this->peek()) {

    case '/':

     for (;;) {

      $c = $this->get();

      if (ord($c) <= self::ORD_LF) {

       return $c;

      }

     }

    case '*':

     $this->get();

     for (;;) {

      switch($this->get()) {

       case '*':

        if ($this->peek() === '/') {

         $this->get();

         return ' ';

        }

        break;

       case null:

        throw new JSMinException('Unterminated comment.');

      }

     }

    default:

     return $c;

   }

  }

  return $c;

 }

 /**

  * Get next char. If is ctrl character, translate to a space or newline.

  *

  * @uses get()

  * @return string|null

  */

 protected function peek() {

  $this->lookAhead = $this->get();

  return $this->lookAhead;

 }

}

// -- Exceptions ---------------------------------------------------------------

class JSMinException extends Exception {}

?>