Added the @transient decorator.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "hydrate-mongodb",
   "description": "An Object Document Mapper (ODM) for MongoDB.",
-  "version": "0.2.22",
+  "version": "0.2.23",
   "author": {
     "name": "Artifact Health, LLC",
     "url": "http://www.artifacthealth.com"

src/mapping/providers/annotations.ts

@@ -796,4 +796,20 @@ function getParentMapping(context: MappingBuilderContext, type: Type): MappingMo
             return <MappingModel.ClassMapping>builder.mapping;
         }
     }
-}
+}
+
+/**
+ * @hidden
+ */
+export class TransientAnnotation implements PropertyAnnotation {
+
+    toString(): string {
+        return "@Transient";
+    }
+
+    processPropertyAnnotation(context: MappingBuilderContext, mapping: MappingModel.ObjectMapping, property: MappingModel.Property, symbol: Property, annotation: Annotation): void {
+
+        property.field = null;
+        property.setFlags(MappingModel.PropertyFlags.Ignored);
+    }
+}

src/mapping/providers/decorators.ts

@@ -30,7 +30,7 @@ import {
     PreUpdateAnnotation,
     PostUpdateAnnotation,
     PreRemoveAnnotation,
-    PostRemoveAnnotation
+    PostRemoveAnnotation, TransientAnnotation
 } from "./annotations";
 
 import {PropertyConverter} from "../mappingModel";
@@ -638,6 +638,27 @@ export declare function PreRemove(): PropertyDecorator;
  */
 export declare function PostRemove(): PropertyDecorator;
 
+/**
+ * Specifies that a property should not be persisted.
+ *
+ * Properties are mapped to persistent document fields on an opt-in basis. *All properties that are decorated are
+ * mapped.* However, if you wish to prevent a decorated property from being mapped, decorate that property with the
+ * Transient decorator as demonstrated below.
+ *
+ * ### Example
+ *
+ * ```typescript
+ *  @Entity()
+ *  export class User {
+ *
+ *      @Transient()
+ *      @SomeOtherDecorator()
+ *      private _something: string;
+ *  }
+ * ```
+ */
+export declare function Transient(): PropertyDecorator;
+
 
 exports.Entity = makeDecorator(EntityAnnotation);
 exports.Embeddable = makeDecorator(EmbeddableAnnotation);
@@ -664,5 +685,6 @@ exports.PreUpdate = makeDecorator(PreUpdateAnnotation);
 exports.PostUpdate = makeDecorator(PostUpdateAnnotation);
 exports.PreRemove = makeDecorator(PreRemoveAnnotation);
 exports.PostRemove = makeDecorator(PostRemoveAnnotation);
+exports.Transient = makeDecorator(TransientAnnotation);
 
 

tests/fixtures/annotations/transient.ts

@@ -0,0 +1,8 @@
+import { Entity, Transient } from "../../../src/mapping/providers/decorators";
+
+@Entity()
+export class A {
+
+    @Transient()
+    a: string;
+}

tests/mapping/providers/annotationMappingProvider.tests.ts

@@ -420,6 +420,30 @@ describe('AnnotationMappingProvider', () => {
                 });
             });
         });
+
+        describe('@transient', () => {
+
+            it("sets property as ignored", (done) => {
+
+                getTransientFieldMapping(done, (property) => assert.isTrue(property.hasFlags(MappingModel.PropertyFlags.Ignored)));
+            });
+
+            it("sets field name to null.", (done) => {
+
+                getTransientFieldMapping(done, (property) => assert.isNull(property.field));
+            });
+
+            function getTransientFieldMapping(done: Callback, callback: (mapping: Property) => void): void {
+
+                processFixture("transient", done, (results) => {
+
+                    var classMapping = findMapping(results, "A");
+                    var property = classMapping.getProperty("a");
+                    assert.ok(property, "Unable to get property 'a' on class 'A' in fixture 'transient'.");
+                    callback(property);
+                });
+            }
+        });
     });
 });