prevent double navigations to the same view

ionic/components/nav/nav-router.ts

@@ -49,6 +49,11 @@ export class NavRouter extends RouterOutlet {
     var componentType = nextInstruction.componentType;
     var childRouter = this._parentRouter.childRouter(componentType);
 
+    // prevent double navigations to the same view
+    var lastView = this.nav.last();
+    if (lastView && lastView.componentType === componentType && lastView.params.data === nextInstruction.params) {
+      return Promise.resolve();
+    }
 
     // tell the ViewController which componentType, and it's params, to navigate to
     return this.nav.push(componentType, nextInstruction.params);

ionic/components/view/view-controller.ts

@@ -640,6 +640,34 @@ export class ViewController extends Ion {
     util.array.remove(this.items, itemOrIndex);
   }
 
+  /**
+   * First view item in this view controller's stack. This would
+   * not return an item which is about to be destroyed.
+   * @returns {TODO} TODO
+   */
+  first() {
+    for (let i = 0, l = this.items.length; i < l; i++) {
+      if (!this.items[i].shouldDestroy) {
+        return this.items[i];
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Last view item in this view controller's stack. This would
+   * not return an item which is about to be destroyed.
+   * @returns {TODO} TODO
+   */
+  last() {
+    for (let i = this.items.length - 1; i >= 0; i--) {
+      if (!this.items[i].shouldDestroy) {
+        return this.items[i];
+      }
+    }
+    return null;
+  }
+
   /**
    * TODO
    * @param {TODO} item  TODO