Add canUndo and canRedo

pangratz · May 16, 2012 · 53f1702 · 53f1702
1 parent c1af27e
commit 53f1702
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diff --git a/app/lib/memento.js b/app/lib/memento.js
@@ -20,6 +20,14 @@ Ember.Memento = Ember.Mixin.create({
         return length - mementoIndex - 1;
     }.property('_mementoIndex', '_memento.length').cacheable(),
 
+    canUndo: function() {
+        return this.get('undoCount') > 0;
+    }.property('undoCount').cacheable(),
+
+    canRedo: function() {
+        return this.get('redoCount') > 0;
+    }.property('redoCount').cacheable(),
+
     _mementoSizeChanged: function() {
         this._updateMemento();
     }.observes('mementoSize'),

diff --git a/app/tests/memento_tests.js b/app/tests/memento_tests.js
@@ -635,6 +635,57 @@ function() {
     equal(get(obj, 'redoCount'), 0, 'redoCount stays 0');
 });
 
+module("canUndo AND canRedo", {
+    teardown: cleanObj
+});
+
+test("they are true when a undo/redo is possible",
+function() {
+    obj = Ember.Object.create(Ember.Memento, {
+        mementoProperties: 'str'.w(),
+
+        str: 'frozen'
+    });
+
+    equal(get(obj, 'canUndo'), false);
+    equal(get(obj, 'canRedo'), false);
+
+    set(obj, 'str', 'banana');
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), false);
+
+    set(obj, 'str', 'Frozen Banana');
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), false);
+
+    obj.undo();
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), true);
+
+    obj.undo();
+
+    equal(get(obj, 'canUndo'), false);
+    equal(get(obj, 'canRedo'), true);
+
+    obj.redo();
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), true);
+
+    obj.redo();
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), false);
+
+    obj.redo();
+
+    equal(get(obj, 'canUndo'), true);
+    equal(get(obj, 'canRedo'), false);
+});
+
 module("clearHistory", {
     teardown: cleanObj
 });