From 7f6b3e81a2efec7623bbe288b62d4d9664e3bb79 Mon Sep 17 00:00:00 2001
From: Tobie Langel <tobie.langel@gmail.com>
Date: Thu, 11 Dec 2008 17:03:10 +0100
Subject: [PATCH] Overwrite Array#concat method for handling the arguments
 object in Opera.

---
 src/lang/array.js       | 19 +++++++++++++------
 test/unit/array_test.js |  5 +++++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/lang/array.js b/src/lang/array.js
index c5de0c5..9597ac1 100644
--- a/src/lang/array.js
+++ b/src/lang/array.js
@@ -134,14 +134,14 @@ Array.from = $A;
   }
   
   function concat() {
-    var array = [];
-    for (var i = 0, length = this.length; i < length; i++) array.push(this[i]);
+    var array = slice.call(this, 0), item;
     for (var i = 0, length = arguments.length; i < length; i++) {
-      if (Object.isArray(arguments[i])) {
-        for (var j = 0, arrayLength = arguments[i].length; j < arrayLength; j++) 
-          array.push(arguments[i][j]);
+      item = arguments[i];
+      if (Object.isArray(item) && !('callee' in item)) {
+        for (var j = 0, arrayLength = item.length; j < arrayLength; j++)
+          array.push(item[j]);
       } else { 
-        array.push(arguments[i]);
+        array.push(item);
       }
     }
     return array;
@@ -171,6 +171,13 @@ Array.from = $A;
     toJSON:    toJSON
   });
   
+  // fix for opera
+  var CONCAT_ARGUMENTS_BUGGY = (function() {
+    return [].concat(arguments)[0][0] !== 1;
+  })(1,2)
+  
+  if (CONCAT_ARGUMENTS_BUGGY) arrayProto.concat = concat;
+  
   // use native browser JS 1.6 implementation if available
   if (!arrayProto.indexOf) arrayProto.indexOf = indexOf;
   if (!arrayProto.lastIndexOf) arrayProto.lastIndexOf = lastIndexOf;
diff --git a/test/unit/array_test.js b/test/unit/array_test.js
index b172075..88d8fad 100644
--- a/test/unit/array_test.js
+++ b/test/unit/array_test.js
@@ -185,5 +185,10 @@ new Test.Unit.Runner({
     this.assertEnumEqual(['a'], $w('a '));
     this.assertEnumEqual(['a'], $w(' a'));
     this.assertEnumEqual(['a', 'b', 'c', 'd'], $w(' a   b\nc\t\nd\n'));
+  },
+  
+  testConcat: function(){
+    var args = (function() { return [].concat(arguments) })(1, 2);
+    this.assertIdentical(1, args[0][0]);
   }
 });
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