diff --git a/lib/fp/base.js b/lib/fp/base.js
index d08b9d368..69f47979a 100644
--- a/lib/fp/base.js
+++ b/lib/fp/base.js
@@ -56,58 +56,33 @@ function baseConvert(util, name, func) {
     };
   };
 
-  var immutArrayWrap = function(func) {
-    return function() {
-      var index = -1,
-          length = arguments.length,
-          args = Array(length);
+  var cloneArray = function(array) {
+    var length = array ? array.length : 0,
+        result = Array(length);
 
-      while (length--) {
-        args[length] = arguments[length];
-      }
-      var array = args[0];
-      length = array ? array.length : 0;
+    while (length--) {
+      result[length] = array[length];
+    }
+    return result;
+  };
 
-      args[0] = Array(length);
-      while (++index < length) {
-        args[0][index] = array[index];
-      }
-      func.apply(undefined, args);
-      return args[0];
+  var createCloner = function(func) {
+    return function(object) {
+      return func({}, object);
     };
   };
 
-  var immutObjectWrap = function(func) {
-    return function() {
-      var index = -1,
-          length = arguments.length,
-          args = Array(length);
-
-      while (++index < length) {
-        args[index] = arguments[index];
-      }
-      args[0] = func({}, args[0]);
-      func.apply(undefined, args);
-      return args[0];
-    };
-  };
-
-  var immutSetWrap = function(func) {
-    return function() {
-      var index = -1,
-          length = arguments.length,
-          args = Array(length);
-
-      while (++index < length) {
-        args[index] = arguments[index];
-      }
-      args[0] = cloneDeep(args[0]);
-      func.apply(undefined, args);
-      return args[0];
-    };
+  var immutWrap = function(func, cloner) {
+    return overArg(func, cloner, true);
   };
 
   var iterateeAry = function(func, n) {
+    return overArg(func, function(func) {
+      return baseAry(func, n);
+    });
+  };
+
+  var overArg = function(func, iteratee, retArg) {
     return function() {
       var length = arguments.length,
           args = Array(length);
@@ -115,8 +90,9 @@ function baseConvert(util, name, func) {
       while (length--) {
         args[length] = arguments[length];
       }
-      args[0] = baseAry(args[0], n);
-      return func.apply(undefined, args);
+      args[0] = iteratee(args[0]);
+      var result = func.apply(undefined, args);
+      return retArg ? args[0] : result;
     };
   };
 
@@ -172,13 +148,13 @@ function baseConvert(util, name, func) {
       return wrapper(func);
     }
     if (mutateMap.array[name]) {
-      func = immutArrayWrap(func);
+      func = immutWrap(func, cloneArray);
     }
     else if (mutateMap.object[name]) {
-      func = immutObjectWrap(func);
+      func = immutWrap(func, createCloner(func));
     }
     else if (mutateMap.set[name]) {
-      func = immutSetWrap(func);
+      func = immutWrap(func, cloneDeep);
     }
     var result;
     each(mapping.caps, function(cap) {