perf(nav): avoid running zone when it is not needed

src/navigation/nav-controller-base.ts

@@ -117,7 +117,7 @@ export class NavControllerBase extends Ion implements NavController {
     }, done);
   }
 
-  popAll() {
+  popAll(): Promise<any[]> {
     let promises: any[] = [];
     for (var i = this._views.length - 1; i >= 0; i--) {
       promises.push(this.pop(null));
@@ -133,6 +133,10 @@ export class NavControllerBase extends Ion implements NavController {
     }, done);
   }
 
+  removeView(viewController: ViewController, opts?: NavOptions, done?: Function): Promise<any> {
+    return this.remove(this.indexOf(viewController), 1, opts, done);
+  }
+
   setRoot(pageOrViewCtrl: any, params?: any, opts?: NavOptions, done?: Function): Promise<any> {
     let viewControllers = [convertToView(this._linker, pageOrViewCtrl, params)];
     return this._setPages(viewControllers, opts, done);
@@ -330,15 +334,16 @@ export class NavControllerBase extends Ion implements NavController {
     const opts = ti.opts || {};
     const insertViews = ti.insertViews;
     const removeStart = ti.removeStart;
-    let view;
-    let destroyQueue: ViewController[] = [];
+    let view: ViewController;
+    let i: number;
+    let destroyQueue: ViewController[];
 
     // there are views to remove
     if (isPresent(removeStart)) {
       assert(removeStart >= 0, 'removeStart can not be negative');
       assert(ti.removeCount >= 0, 'removeCount can not be negative');
-
-      for (var i = 0; i < ti.removeCount; i++) {
+      destroyQueue = [];
+      for (i = 0; i < ti.removeCount; i++) {
         view = this._views[i + removeStart];
         if (view && view !== enteringView && view !== leavingView) {
           destroyQueue.push(view);
@@ -356,7 +361,7 @@ export class NavControllerBase extends Ion implements NavController {
       }
 
       // add the views to the
-      for (var i = 0; i < insertViews.length; i++) {
+      for (i = 0; i < insertViews.length; i++) {
         view = insertViews[i];
         this._insertViewAt(view, ti.insertStart + i);
       }
@@ -366,22 +371,26 @@ export class NavControllerBase extends Ion implements NavController {
         opts.direction = opts.direction || DIRECTION_FORWARD;
       }
     }
+
     // if the views to be removed are in the beginning or middle
     // and there is not a view that needs to visually transition out
     // then just destroy them and don't transition anything
     // batch all of lifecycles together
     // let's make sure, callbacks are zoned
-    this._zone.run(() => {
-      for (view of destroyQueue) {
-        this._willLeave(view);
-        this._didLeave(view);
-        this._willUnload(view);
-      }
-    });
+    if (destroyQueue && destroyQueue.length > 0) {
+      this._zone.run(() => {
+        for (i = 0; i < destroyQueue.length; i++) {
+          view = destroyQueue[i];
+          this._willLeave(view);
+          this._didLeave(view);
+          this._willUnload(view);
+        }
+      });
 
-    // once all lifecycle events has been delivered, we can safely detroy the views
-    for (view of destroyQueue) {
-      this._destroyView(view);
+      // once all lifecycle events has been delivered, we can safely detroy the views
+      for (i = 0; i < destroyQueue.length; i++) {
+        this._destroyView(destroyQueue[i]);
+      }
     }
 
     if (ti.enteringRequiresTransition || ti.leavingRequiresTransition && enteringView !== leavingView) {

src/navigation/nav-controller.ts

@@ -452,6 +452,15 @@ export abstract class NavController {
    */
   abstract remove(startIndex: number, removeCount?: number, opts?: NavOptions, done?: Function): Promise<any>;
 
+  /**
+   * Removes the specified view controller from the nav stack.
+   *
+   * @param {ViewController} [viewController] The viewcontroller to remove.
+   * @param {object} [opts={}] Any options you want to use pass to transtion.
+   * @returns {Promise} Returns a promise which is resolved when the transition has completed.
+   */
+  abstract removeView(viewController: ViewController, opts?: NavOptions, done?: Function): Promise<any>;
+
   /**
    * Set the root for the current navigation stack.
    * @param {Page|ViewController} page  The name of the component you want to push on the navigation stack.

src/navigation/view-controller.ts

@@ -179,7 +179,7 @@ export class ViewController {
 
     let options = assign({}, this._leavingOpts, navOptions);
     this._onWillDismiss && this._onWillDismiss(data, role);
-    return this._nav.remove(this._nav.indexOf(this), 1, options).then(() => {
+    return this._nav.removeView(this, options).then(() => {
       this._onDidDismiss && this._onDidDismiss(data, role);
       this._onDidDismiss = null;
       return data;