Added 'areEqual' to PropertyConverter

package.json

@@ -1,7 +1,7 @@
 {
   "name": "hydrate-mongodb",
   "description": "An Object Document Mapper (ODM) for MongoDB.",
-  "version": "0.7.2",
+  "version": "0.8.0",
   "author": {
     "name": "Artifact Health, LLC",
     "url": "http://www.artifacthealth.com"

src/config/configuration.ts

@@ -221,8 +221,25 @@ export interface IdentityGenerator {
  */
 export interface PropertyConverter {
 
+    /**
+     * Converts an object property value to a document field value.
+     * @param property The property value to convert.
+     */
     convertToDocumentField(property: any): any;
+
+    /**
+     * Converts a document field value to an object property value.
+     * @param field The field value to convert.
+     */
     convertToObjectProperty(field: any): any;
+
+    /**
+     * Returns true if the document field values are equal; otherwise, returns false. This method is only called if both values are not
+     * null and the values are not strictly equal.
+     * @param field1 First document field value.
+     * @param field2 Other document field value.
+     */
+    areEqual(field1: any, field2: any): boolean;
 }
 
 /**

src/mapping/bufferMapping.ts

@@ -36,4 +36,11 @@ export class BufferMapping extends MappingBase {
         return new Binary(value);
     }
 
+    areEqual(documentValue1: any, documentValue2: any): boolean {
+
+        if (documentValue1 === documentValue2) return true;
+        if (documentValue1 === null || documentValue2 === null) return false;
+
+        return documentValue1.value(true).equals(documentValue2.value(true));
+    }
 }

src/mapping/converterMapping.ts

@@ -42,4 +42,13 @@ export class ConverterMapping extends MappingBase {
 
         return result;
     }
+
+    areEqual(documentValue1: any, documentValue2: any): boolean {
+
+        if (documentValue1 === documentValue2) return true;
+        if (documentValue1 === null || documentValue2 === null) return false;
+        if (documentValue1 !== documentValue1 && documentValue2 !== documentValue2) return true; // NaN === NaN
+
+        return false;
+    }
 }

src/mapping/mappingModel.ts

@@ -467,8 +467,25 @@ export namespace MappingModel {
 
 export interface PropertyConverter {
 
+    /**
+     * Converts an object property value to a document field value.
+     * @param property The property value to convert.
+     */
     convertToDocumentField(property: any): any;
+
+    /**
+     * Converts a document field value to an object property value.
+     * @param field The field value to convert.
+     */
     convertToObjectProperty(field: any): any;
+
+    /**
+     * Returns true if the document field values are equal; otherwise, returns false. This method is only called if both values are not
+     * null and the values are not strictly equal.
+     * @param field1 First document field value.
+     * @param field2 Other document field value.
+     */
+    areEqual(field1: any, field2: any): boolean;
 }
 
 export const enum ChangeTrackingType {

tests/fixtures/annotations/converter.ts

@@ -15,7 +15,7 @@ class SomeConverter implements PropertyConverter {
         switch(property) {
             case MyEnum.value1:
                 return "A";
-            case MyEnum.value1:
+            case MyEnum.value2:
                 return "B";
             case MyEnum.value3:
                 return "C";
@@ -33,6 +33,11 @@ class SomeConverter implements PropertyConverter {
                 return MyEnum.value3;
         }
     }
+
+    areEqual(field1: any, field2: any): boolean {
+
+        return field1 === field2;
+    }
 }
 
 @Entity()

tests/fixtures/model.ts

@@ -25,6 +25,11 @@ export class PhoneTypeConverter implements PropertyConverter {
                 return PhoneType.Home;
         }
     }
+
+    areEqual(field1: any, field2: any): boolean {
+
+        return field1 === field2;
+    }
 }
 
 @Embeddable()

tests/mapping/bufferMapping.tests.ts

@@ -37,4 +37,57 @@ describe('BufferMapping', () => {
         });
     });
 
+    describe("areEqual", () => {
+
+        it('returns true if both values are null', () => {
+
+            var mapping = new BufferMapping();
+            assert.isTrue(mapping.areEqual(null, null));
+        });
+
+        it('return false if one value is null and the other is not', () => {
+
+            var mapping = new BufferMapping();
+
+            assert.isFalse(mapping.areEqual(null, {}));
+            assert.isFalse(mapping.areEqual({}, null));
+        });
+
+        it("returns true if the contents of the Buffers are equal", () => {
+
+            compareBuffers("Some value", "Some value", true);
+        });
+
+        it("returns false if the contents of the Buffers are not equal", () => {
+
+            compareBuffers("Some value", "Some other value", false);
+        });
+
+        function compareBuffers(text1: string, text2: string, result: boolean): void {
+
+            var mapping = new BufferMapping();
+
+            var buffer1 = new Buffer(text1),
+                buffer2 = new Buffer(text2);
+
+            var context1 = new WriteContext(),
+                context2 = new WriteContext();
+
+            var value1 = mapping.write(context1, buffer1),
+                value2 = mapping.write(context2, buffer2);
+
+            assert.ok(value1);
+            assert.ok(value2);
+
+            if (context1.hasErrors) {
+                throw new Error(context1.getErrorMessage());
+            }
+
+            if (context2.hasErrors) {
+                throw new Error(context2.getErrorMessage());
+            }
+
+            assert.equal(mapping.areEqual(value1, value2), result);
+        }
+    });
 });

tests/mapping/providers/annotationMappingProvider.tests.ts

@@ -532,6 +532,11 @@ class MyEnumConverter implements PropertyConverter {
                 return ConverterFixture.B;
         }
     }
+
+    areEqual(field1: any, field2: any): boolean {
+
+        return field1 === field2;
+    }
 }
 
 class PointConverter implements PropertyConverter {
@@ -546,4 +551,9 @@ class PointConverter implements PropertyConverter {
         var parts = field.split('.');
         return new ConverterOnClassFixture.Point(parts[0], parts[1]);
     }
+
+    areEqual(field1: any, field2: any): boolean {
+
+        return field1 === field2;
+    }
 }