Ensure optimized isPlainObject works with objects from other documents.

Former-commit-id: 2f782b3dfc19e7ea3274132c31cd408ee2387021

build.js

@@ -572,17 +572,6 @@
     return source.replace(/(?:\s*\/\/.*)*\n( +)if *\(isFunction\(\/x\/[\s\S]+?};\n\1}/, '');
   }
 
-  /**
-   * Removes the `isPlainObject` fallback from `source`.
-   *
-   * @private
-   * @param {String} source The source to process.
-   * @returns {String} Returns the source with the `isPlainObject` fallback removed.
-   */
-  function removeIsPlainObjectFallback(source) {
-    return source.replace(/(?:\s*\/\/.*)*\n( +)if *\(!isPlainObject[\s\S]+?};\n\1}/, '');
-  }
-
   /**
    * Removes the `Object.keys` object iteration optimization from `source`.
    *
@@ -1003,7 +992,6 @@
 
     if (!isUnderscore) {
       source = removeIsArgumentsFallback(source);
-      source = removeIsPlainObjectFallback(source);
       source = removeNoArgsClass(source);
     }
 
@@ -1131,7 +1119,6 @@
     source = removeVar(source, 'reNative');
   }
   if (isRemoved(source, 'createIterator', 'clone', 'merge')) {
-    source = removeIsPlainObjectFallback(source);
     source = source.replace(/(?:\n +\/\*[^*]*\*+(?:[^\/][^*]*\*+)*\/)?\n *var iteratesOwnLast;|.+?iteratesOwnLast *=.+/g, '');
   }
   if (isRemoved(source, 'createIterator', 'isEqual')) {

lodash.js

@@ -966,9 +966,7 @@
   }
 
   /**
-   * Checks if a given `value` is an object created by the `Object` constructor
+   * A fallback implementation of `isPlainObject`.
-   * assuming objects created by the `Object` constructor have no inherited
-   * enumerable properties and that there are no `Object.prototype` extensions.
    *
    * @private
    * @param {Mixed} value The value to check.
@@ -977,14 +975,7 @@
    * @returns {Boolean} Returns `true` if the `value` is a plain `Object` object,
    *  else `false`.
    */
-  function isPlainObject(value, skipArgsCheck) {
+  function isPlainFallback(value, skipArgsCheck) {
-    return value
-      ? value == ObjectProto || (value.__proto__ == ObjectProto && (skipArgsCheck || !isArguments(value)))
-      : false;
-  }
-  // fallback for IE
-  if (!isPlainObject(objectTypes)) {
-    isPlainObject = function(value, skipArgsCheck) {
     // avoid non-objects and false positives for `arguments` objects
     var result = false;
     if (!(value && typeof value == 'object') || (!skipArgsCheck && isArguments(value))) {
@@ -1015,9 +1006,32 @@
       return result === false || hasOwnProperty.call(value, result);
     }
     return result;
-    };
   }
 
+  /**
+   * Checks if a given `value` is an object created by the `Object` constructor
+   * assuming objects created by the `Object` constructor have no inherited
+   * enumerable properties and that there are no `Object.prototype` extensions.
+   *
+   * @private
+   * @param {Mixed} value The value to check.
+   * @param {Boolean} [skipArgsCheck=false] Internally used to skip checks for
+   *  `arguments` objects.
+   * @returns {Boolean} Returns `true` if the `value` is a plain `Object` object,
+   *  else `false`.
+   */
+  var isPlainObject = objectTypes.__proto__ != ObjectProto ? isPlainFallback : function(value, skipArgsCheck) {
+    if (!value) {
+      return false;
+    }
+    var valueOf = value.valueOf,
+        objProto = typeof valueOf == 'function' && valueOf.__proto__.__proto__;
+
+    return objProto
+      ? value == objProto || (value.__proto__ == objProto && (skipArgsCheck || !isArguments(value)))
+      : isPlainFallback(value);
+  };
+
   /**
    * A shim implementation of `Object.keys` that produces an array of the given
    * object's own enumerable property names.

test/index.html

@@ -33,7 +33,7 @@
 			delete Object._keys;
 
 			// set to test `_.noConflict`
-			_ = 1;
+			_ = {};
 
 			// load Lo-Dash again to overwrite the existing `_` value
 			document.write('<script src="../' + QUnit.config.lodashFilename + '.js"><\/script>');

test/test.js

@@ -83,6 +83,23 @@
 
   /*--------------------------------------------------------------------------*/
 
+  // add object from iframe
+  (function() {
+    if (!window.document) {
+      return;
+    }
+    var body = document.body,
+        iframe = document.createElement('iframe');
+
+    iframe.frameBorder = iframe.height = iframe.width = 0;
+    body.appendChild(iframe);
+    var idoc = (idoc = iframe.contentDocument || iframe.contentWindow).document || idoc;
+    idoc.write("<script>parent._._object = { 'a': 1, 'b': 2, 'c': 3 };<\/script>");
+    idoc.close();
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   // explicitly call `QUnit.module()` instead of `module()`
   // in case we are in a CLI environment
   QUnit.module('lodash');
@@ -191,6 +208,7 @@
       'boolean object': Object(false),
       'an object': { 'a': 0, 'b': 1, 'c': 3 },
       'an object with object values': { 'a': /a/, 'b': ['B'], 'c': { 'C': 1 } },
+      'an object from another document': _._object || {},
       'null': null,
       'a number': 3,
       'a number object': Object(3),
@@ -205,12 +223,8 @@
     _.forOwn(objects, function(object, key) {
       test('should deep clone ' + key + ' correctly', function() {
         var clone = _.clone(object, true);
+        ok(_.isEqual(object, clone));
 
-        if (object == null) {
-          equal(clone, object);
-        } else {
-          deepEqual(clone.valueOf(), object.valueOf());
-        }
         if (_.isObject(object)) {
           ok(clone !== object);
         } else {
@@ -747,21 +761,10 @@
     });
 
     test('should return `true` for like-objects from different documents', function() {
-      if (window.document) {
-        var body = document.body,
-            iframe = document.createElement('iframe'),
-            object = { 'a': 1, 'b': 2, 'c': 3 };
-
-        body.appendChild(iframe);
-        var idoc = (idoc = iframe.contentDocument || iframe.contentWindow).document || idoc;
-        idoc.write("<script>parent._._object = { 'a': 1, 'b': 2, 'c': 3 };<\/script>");
-        idoc.close();
-      }
       // ensure `_._object` is assigned (unassigned in Opera 10.00)
       if (_._object) {
+        var object = { 'a': 1, 'b': 2, 'c': 3 };
         equal(_.isEqual(object, _._object), true);
-        body.removeChild(iframe);
-        delete _._object;
       }
       else {
         skipTest();