Use lodash's map, it's faster

lib/map.js

@@ -1,13 +1,21 @@
 import update from './update';
 import wrap from './wrap';
 import forEach from 'lodash/collection/forEach';
+import mapArray from 'lodash/collection/map';
+import mapObject from 'lodash/object/mapValues';
 
-function clone(object) {
-  if (Array.isArray(object)) {
-    return [...object];
-  }
+function shallowEqual(object, otherObject) {
+  let equal = true;
+  forEach(otherObject, (value, key) => {
+    if (value !== object[key]) {
+      equal = false;
 
-  return { ...object };
+      // exit early
+      return false;
+    }
+  });
+
+  return equal;
 }
 
 function map(iteratee, object) {
@@ -15,19 +23,16 @@ function map(iteratee, object) {
     iteratee :
     update(iteratee);
 
-  let newObject;
+  const mapper = Array.isArray(object) ?
+    mapArray :
+    mapObject;
 
-  forEach(object, (value, index) => {
-    const newValue = updater(value, index);
+  const newObject = mapper(object, updater);
+  const equal = shallowEqual(object, newObject);
 
-    if (newValue === value) return;
-
-    newObject = newObject || clone(object);
-
-    newObject[index] = newValue;
-  });
-
-  return newObject || object;
+  return equal ?
+    object :
+    newObject;
 }
 
 export default wrap(map);