Alternative fix for #393

This keeps whitespace around comments while they're
extracted from the content, and leaves it up to
stripWhitespace later on to strip when appropriate,
ensureing that only the contents of the comment are
preserved or stripped (in stripComments), not the
whitespace around it.

src/JS.php

@@ -199,28 +199,24 @@ protected function stripComments()
         $minifier = $this;
         $callback = function ($match) use ($minifier) {
             if (
-                substr($match[1], 0, 1) === '!' ||
-                strpos($match[1], '@license') !== false ||
-                strpos($match[1], '@preserve') !== false
+                substr($match[2], 0, 1) === '!' ||
+                strpos($match[2], '@license') !== false ||
+                strpos($match[2], '@preserve') !== false
             ) {
                 // preserve multi-line comments that start with /*!
                 // or contain @license or @preserve annotations
                 $count = count($minifier->extracted);
                 $placeholder = '/*'.$count.'*/';
                 $minifier->extracted[$placeholder] = $match[0];
 
-                return $placeholder . ($match[3] ? $match[2] . $match[3] : '');
-            }
-            // should not remove the \n before a var|let etc. at this stage, because it could be a case like this: var a=1\n/*comment*/\nvar b=2;
-            if($match[3]) {
-                return $match[2] . $match[3];
+                return $match[1] . $placeholder . $match[3];
             }
 
-            return '';
+            return $match[1] . $match[3];
         };
 
         // multi-line comments
-        $this->registerPattern('/\n?\/\*(.*?)\*\/(\n?)(var|let|const|enum|function|class|)/s', $callback);
+        $this->registerPattern('/(\n?)\/\*(.*?)\*\/(\n?)/s', $callback);
 
         // single-line comments
         $this->registerPattern('/\/\/.*$/m', '');

tests/js/JSTest.php

@@ -1344,6 +1344,21 @@ function someOtherFunction() {
             'var crypt=function(){}
 var Sbox=2',
         );
+        $tests[] = array(
+            'a = function() {}
+/* some comment to be removed */
+b = 2',
+            'a=function(){}
+b=2',
+        );
+        $tests[] = array(
+            'a = function() {}
+/* @preserve some comment to be preserved */
+b = 2',
+            'a=function(){}
+/* @preserve some comment to be preserved */
+b=2',
+        );
 
         // known minified files to help doublecheck changes in places not yet
         // anticipated in these tests
@@ -1359,13 +1374,12 @@ function someOtherFunction() {
             }
         }
 
-        //some other files that are minified correctly, ensure they stay like this
+        // some other files that are minified correctly, ensure they stay like this
         // https://github.com/matthiasmullie/minify/issues/393
         $source = trim(file_get_contents(__DIR__.'/sample/source/Decrypt.js'));
         $minified = trim(file_get_contents(__DIR__.'/sample/minified2/Decrypt.min.js'));
         $tests[] = array($source, $minified);
 
-
         return $tests;
     }
 }