Merge branch 'add_undoCount_redoCount', this closes #5

app/lib/memento.js

@@ -1,4 +1,5 @@
 Ember.Memento = Ember.Mixin.create({
+
     // holds all history items
     _memento: [],
 
@@ -9,6 +10,16 @@ Ember.Memento = Ember.Mixin.create({
     */
     _mementoIndex: -1,
 
+    undoCount: function() {
+        return this.get('_mementoIndex') + 1;
+    }.property('_mementoIndex').cacheable(),
+
+    redoCount: function() {
+        var length = this.getPath('_memento.length');
+        var mementoIndex = this.get('_mementoIndex');
+        return length - mementoIndex - 1;
+    }.property('_mementoIndex', '_memento.length').cacheable(),
+
     _mementoSizeChanged: function() {
         this._updateMemento();
     }.observes('mementoSize'),
@@ -123,6 +134,9 @@ Ember.Memento = Ember.Mixin.create({
     },
 
     init: function() {
+        this.set('_memento', []);
+        this.set('_mementoIndex', -1);
+
         // iterate over all mementoProperties and add observers
         var props = this.get('mementoProperties');
         props.forEach(function(item) {

app/tests/memento_tests.js

@@ -505,6 +505,136 @@ function() {
     deepEqual(get(obj, 'array'), [1, 2, 3], 'redo changes array');
 });
 
+module("undoCount AND redoCount", {
+    teardown: cleanObj
+});
+
+test("are initially 0",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+
+        str: 'hansi'
+    });
+
+    equal(get(obj, 'undoCount'), 0, 'undoCount is initially 0');
+    equal(get(obj, 'redoCount'), 0, 'redoCount is initially 0');
+});
+
+test("change when a property is set",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+        str: 'hansi'
+    });
+
+    equal(get(obj, 'undoCount'), 0, 'precond - undoCount is initially 0');
+    equal(get(obj, 'redoCount'), 0, 'precond - redoCount is initially 0');
+
+    set(obj, 'str', 'frozen banana');
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is 1 when a undo can be done');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+});
+
+test("change when a undo is done",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+        str: 'hansi'
+    });
+
+    equal(get(obj, 'undoCount'), 0, 'precond - undoCount is initially 0');
+    equal(get(obj, 'redoCount'), 0, 'precond - redoCount is initially 0');
+
+    set(obj, 'str', 'frozen banana');
+
+    equal(get(obj, 'undoCount'), 1, 'precond - undoCount is 1 when a undo can be done');
+    equal(get(obj, 'redoCount'), 0, 'precond - redoCount stays 0');
+
+    obj.undo();
+
+    equal(get(obj, 'undoCount'), 0, 'undoCount is 0 after an undo');
+    equal(get(obj, 'redoCount'), 1, 'redoCount is 1 after an undo');
+});
+
+test("complex example",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+        str: 'hansi'
+    });
+
+    equal(get(obj, 'undoCount'), 0, 'precond - undoCount is initially 0');
+    equal(get(obj, 'redoCount'), 0, 'precond - redoCount is initially 0');
+
+    set(obj, 'str', 'frozen banana');
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is 1 when a undo can be done');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+
+    set(obj, 'str', 'hubert');
+
+    equal(get(obj, 'undoCount'), 2, 'undoCount is increased when a property changes');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+
+    obj.undo();
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is 1 after an undo');
+    equal(get(obj, 'redoCount'), 1, 'redoCount is 1 after an undo');
+
+    obj.undo();
+
+    equal(get(obj, 'undoCount'), 0, 'undoCount is 0 after an undo');
+    equal(get(obj, 'redoCount'), 2, 'redoCount is 2 after an undo');
+
+    obj.undo();
+
+    equal(get(obj, 'undoCount'), 0, 'undoCount is 0 after an undo');
+    equal(get(obj, 'redoCount'), 2, 'redoCount is 2 after an undo');
+
+    obj.redo();
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is 1 after an undo');
+    equal(get(obj, 'redoCount'), 1, 'redoCount is 1 after an undo');
+
+    obj.redo();
+
+    equal(get(obj, 'undoCount'), 2, 'undoCount is 2 after an undo');
+    equal(get(obj, 'redoCount'), 0, 'redoCount is 0 after an undo');
+
+    obj.redo();
+
+    equal(get(obj, 'undoCount'), 2, 'undoCount is 2 after an undo');
+    equal(get(obj, 'redoCount'), 0, 'redoCount is 0 after an undo');
+});
+
+test("change when mementoSize is changed",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+        str: 'hansi'
+    });
+
+    equal(get(obj, 'undoCount'), 0, 'precond - undoCount is initially 0');
+    equal(get(obj, 'redoCount'), 0, 'precond - redoCount is initially 0');
+
+    set(obj, 'str', 'frozen banana');
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is 1 when a undo can be done');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+
+    set(obj, 'str', 'hubert');
+
+    equal(get(obj, 'undoCount'), 2, 'undoCount is increased when a property changes');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+
+    set(obj, 'mementoSize', 1);
+
+    equal(get(obj, 'undoCount'), 1, 'undoCount is decreased to 1');
+    equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
+});
+
 module("clearHistory", {
     teardown: cleanObj
 });