diff --git a/src/backend.memory.js b/src/backend.memory.js
index f42aae07..ef17451b 100644
--- a/src/backend.memory.js
+++ b/src/backend.memory.js
@@ -227,12 +227,15 @@ this.recline.Backend.Memory = this.recline.Backend.Memory || {};
     };
 
     this.transform = function(editFunc) {
-      var toUpdate = recline.Data.Transform.mapDocs(this.data, editFunc);
-      // TODO: very inefficient -- could probably just walk the documents and updates in tandem and update
-      _.each(toUpdate.updates, function(record, idx) {
-        self.data[idx] = record;
+      var dfd = $.Deferred();
+      // TODO: should we clone before mapping? Do not see the point atm.
+      self.data = _.map(self.data, editFunc);
+      // now deal with deletes (i.e. nulls)
+      self.data = _.filter(self.data, function(record) {
+        return record != null;
       });
-      return this.save(toUpdate);
+      dfd.resolve();
+      return dfd.promise();
     };
   };
 
diff --git a/test/backend.memory.test.js b/test/backend.memory.test.js
index 5743d6d3..822c64f2 100644
--- a/test/backend.memory.test.js
+++ b/test/backend.memory.test.js
@@ -187,6 +187,31 @@ test('update and delete', function () {
   equal(data.data[0].x, memoryData[1].x);
 });
 
+test('transform', function () {
+  var data = [
+    {a: 1, b: " bla"},
+    {a: 2, b: "foo "},
+    {a: 3, b: "bar"}
+  ];
+  var store = new recline.Backend.Memory.Store(data);
+  store.transform(function(d) {
+    d.a = d.a * 10;
+    return d;
+  })
+  equal(store.data[0].a, 10);
+  equal(store.data[1].a, 20);
+});
+
+test('transform deletes', function () {
+  var data = [{a: 1, b: " bla"},{a: 2, b: "foo "},{a: 3, b: "bar"}];
+  var store = new recline.Backend.Memory.Store(data);
+  store.transform(function(d) {
+    if (d.a == '1') return null;
+    else return d;
+  })
+  equal(store.data.length, 2);
+});
+
 })(this.jQuery);
 
 // ======================================