Add isDirty function to model instances

Changelog.md

@@ -1,3 +1,6 @@
+### v7.1.0
+- Add `isDirty` function to instances ([859](../../pull/859))
+
 ### v7.0.0
 - Update `async` package from v2 to v3 to resolve security vulnerabilities ([858](../../pull/858))
 - Drop support for node < 6 (due to `async` package update)

lib/Instance.js

@@ -670,6 +670,12 @@ function Instance(Model, opts) {
     get: function () { return opts.changes; },
     enumerable: false
   });
+  Object.defineProperty(instance, "isDirty", {
+    value: function () {
+      return opts.changes.length > 0;
+    },
+    enumerable: false
+  });
   Object.defineProperty(instance, "isInstance", {
     value: true,
     enumerable: false

package.json

@@ -12,7 +12,7 @@
     "sqlite",
     "mongodb"
   ],
-  "version": "7.0.0",
+  "version": "7.1.0",
   "license": "MIT",
   "homepage": "http://dresende.github.io/node-orm2",
   "repository": "http://github.com/dresende/node-orm2.git",

test/integration/instance.js

@@ -303,6 +303,35 @@ describe("Model instance", function() {
     });
   });
 
+  describe("#isDirty", function () {
+    var person = null;
+
+    beforeEach(function (done) {
+      Person.create({ name: 'John', age: 44, data: { a: 1 } }, function (err, p) {
+        if (err) return cb(err);
+
+        person = p;
+        done();
+      });
+    });
+
+    it("should return false by default", function () {
+      should.equal(person.isDirty(), false);
+    });
+
+    it("should return false when property is set to same value", function () {
+      should.equal(person.isDirty(), false);
+      person.name = 'John';
+      should.equal(person.isDirty(), false);
+    });
+
+    it("should return true when property is changed", function () {
+      should.equal(person.isDirty(), false);
+      person.name = 'Bob';
+      should.equal(person.isDirty(), true);
+    });
+  });
+
   describe("#isShell", function () {
     it("should return true for shell models", function () {
       should.equal(Person(4).isShell(), true);