Add support for deep cloning maps and sets.

lodash.js

@@ -2437,7 +2437,7 @@
           if (!cloneableTags[tag]) {
             return object ? value : {};
           }
-          result = initCloneByTag(value, tag, isDeep);
+          result = initCloneByTag(value, tag, baseClone, isDeep);
         }
       }
       // Check for circular references and return its corresponding clone.
@@ -2448,11 +2448,18 @@
       }
       stack.set(value, result);
 
+      if (!isArr) {
+        var props = isFull ? getAllKeys(value) : keys(value);
+      }
       // Recursively populate clone (susceptible to call stack limits).
-      (isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
+      arrayEach(props || value, function(subValue, key) {
+        if (props) {
+          key = subValue;
+          subValue = value[key];
+        }
         assignValue(result, key, baseClone(subValue, isDeep, isFull, customizer, key, value, stack));
       });
-      return (isFull && !isArr) ? copySymbols(value, result) : result;
+      return result;
     }
 
     /**
@@ -2768,6 +2775,24 @@
       return (index && index == length) ? object : undefined;
     }
 
+    /**
+     * The base implementation of `getAllKeys` and `getAllKeysIn` which uses
+     * `keysFunc` and `symbolsFunc` to get the enumerable property names and
+     * symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @param {Function} symbolsFunc The function to get the symbols of `object`.
+     * @returns {Array} Returns the array of property names and symbols.
+     */
+    function baseGetAllKeys(object, keysFunc, symbolsFunc) {
+      var result = keysFunc(object);
+      return isArray(object)
+        ? result
+        : arrayPush(result, symbolsFunc(object));
+    }
+
     /**
      * The base implementation of `_.has` without support for deep paths.
      *
@@ -3176,10 +3201,9 @@
       if (object === source) {
         return;
       }
-      var props = (isArray(source) || isTypedArray(source))
-        ? undefined
-        : keysIn(source);
-
+      if (!(isArray(source) || isTypedArray(source))) {
+        var props = keysIn(source);
+      }
       arrayEach(props || source, function(srcValue, key) {
         if (props) {
           key = srcValue;
@@ -3905,10 +3929,13 @@
      *
      * @private
      * @param {Object} map The map to clone.
+     * @param {Function} cloneFunc The function to clone values.
+     * @param {boolean} [isDeep] Specify a deep clone.
      * @returns {Object} Returns the cloned map.
      */
-    function cloneMap(map) {
-      return arrayReduce(mapToArray(map), addMapEntry, new map.constructor);
+    function cloneMap(map, isDeep, cloneFunc) {
+      var array = isDeep ? cloneFunc(mapToArray(map), true) : mapToArray(map);
+      return arrayReduce(array, addMapEntry, new map.constructor);
     }
 
     /**
@@ -3929,10 +3956,13 @@
      *
      * @private
      * @param {Object} set The set to clone.
+     * @param {Function} cloneFunc The function to clone values.
+     * @param {boolean} [isDeep] Specify a deep clone.
      * @returns {Object} Returns the cloned set.
      */
-    function cloneSet(set) {
-      return arrayReduce(setToArray(set), addSetEntry, new set.constructor);
+    function cloneSet(set, isDeep, cloneFunc) {
+      var array = isDeep ? cloneFunc(setToArray(set), true) : setToArray(set);
+      return arrayReduce(array, addSetEntry, new set.constructor);
     }
 
     /**
@@ -4957,7 +4987,18 @@
     }
 
     /**
-     * Creates an array of the own and inherited enumerable property names and
+     * Creates an array of own enumerable property names and symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names and symbols.
+     */
+    function getAllKeys(object) {
+      return baseGetAllKeys(object, keys, getSymbols);
+    }
+
+    /**
+     * Creates an array of own and inherited enumerable property names and
      * symbols of `object`.
      *
      * @private
@@ -4965,10 +5006,7 @@
      * @returns {Array} Returns the array of property names and symbols.
      */
     function getAllKeysIn(object) {
-      var result = keysIn(object);
-      return isArray(object)
-        ? result
-        : arrayPush(result, getSymbolsIn(object));
+      return baseGetAllKeys(object, keysIn, getSymbolsIn);
     }
 
     /**
@@ -5258,10 +5296,11 @@
      * @private
      * @param {Object} object The object to clone.
      * @param {string} tag The `toStringTag` of the object to clone.
+     * @param {Function} cloneFunc The function to clone values.
      * @param {boolean} [isDeep] Specify a deep clone.
      * @returns {Object} Returns the initialized clone.
      */
-    function initCloneByTag(object, tag, isDeep) {
+    function initCloneByTag(object, tag, cloneFunc, isDeep) {
       var Ctor = object.constructor;
       switch (tag) {
         case arrayBufferTag:
@@ -5277,7 +5316,7 @@
           return cloneTypedArray(object, isDeep);
 
         case mapTag:
-          return cloneMap(object);
+          return cloneMap(object, isDeep, cloneFunc);
 
         case numberTag:
         case stringTag:
@@ -5287,7 +5326,7 @@
           return cloneRegExp(object);
 
         case setTag:
-          return cloneSet(object);
+          return cloneSet(object, isDeep, cloneFunc);
 
         case symbolTag:
           return cloneSymbol(object);