Allow multiple map calls

lib/cursor.js

@@ -1003,7 +1003,12 @@ define.classMethod('close', {callback: true, promise:true});
  * @return {Cursor}
  */
 Cursor.prototype.map = function(transform) {
-  this.cursorState.transforms = { doc: transform };
+  if(this.cursorState.transforms && this.cursorState.transforms.doc) {
+    var oldTransform = this.cursorState.transforms.doc;
+    this.cursorState.transforms.doc = function (doc) { return transform(oldTransform(doc)); };
+  } else {
+    this.cursorState.transforms = { doc: transform };
+  }
   return this;
 }
 

test/functional/cursor_tests.js

@@ -3017,6 +3017,53 @@ exports['Should correctly apply map to forEach'] = {
 
       var collection = db.collection('map_forEach');
 
+      // insert all docs
+      collection.insert(docs, configuration.writeConcernMax(), function(err, result) {
+        test.equal(null, err);
+        var total = 0;
+
+        // Create a cursor for the content
+        var cursor = collection.find({})
+          .map(function(x) { return {a:2}; })
+          .map(function(x) { return {a: x.a * x.a }; })
+          .batchSize(5)
+          .limit(10);
+        cursor.forEach(function(doc) {
+          test.equal(4, doc.a);
+        }, function(err, doc) {
+          test.equal(null, err);
+          db.close();
+          test.done();
+        });
+      })
+    });
+  }
+}
+
+/**
+ * @ignore
+ * @api private
+ */
+exports['Should correctly apply multiple uses of map and apply forEach'] = {
+  // Add a tag that our runner can trigger on
+  // in this case we are setting that node needs to be higher than 0.10.X to run
+  metadata: { requires: { topology: ['single', 'replicaset', 'sharded', 'ssl', 'heap', 'wiredtiger'] } },
+
+  // The actual test we wish to run
+  test: function(configuration, test) {
+    var docs = [];
+
+    for(var i = 0; i < 1000; i++) {
+      var d = new Date().getTime() + i*1000;
+      docs[i] = {'a':i, createdAt:new Date(d)};
+    }
+
+    var db = configuration.newDbInstance(configuration.writeConcernMax(), {poolSize:1});
+    db.open(function(err, db) {
+      test.equal(null, err);
+
+      var collection = db.collection('map_mapmapforEach');
+
       // insert all docs
       collection.insert(docs, configuration.writeConcernMax(), function(err, result) {
         test.equal(null, err);