chore(): begin adding ionic components to mono-repo.

packages/ionic-angular/src/navigation/swipe-back.ts

@@ -0,0 +1,67 @@
+import { swipeShouldReset } from '../util/util';
+import { DomController } from '../platform/dom-controller';
+import { GestureController, GESTURE_PRIORITY_GO_BACK_SWIPE, GESTURE_GO_BACK_SWIPE } from '../gestures/gesture-controller';
+import { NavControllerBase } from './nav-controller-base';
+import { Platform } from '../platform/platform';
+import { SlideData } from '../gestures/slide-gesture';
+import { SlideEdgeGesture } from '../gestures/slide-edge-gesture';
+
+/**
+ * @hidden
+ */
+export class SwipeBackGesture extends SlideEdgeGesture {
+
+  constructor(
+    plt: Platform,
+    private _nav: NavControllerBase,
+    gestureCtlr: GestureController,
+    domCtrl: DomController,
+  ) {
+    super(plt, plt.doc().body, {
+      direction: 'x',
+      edge: 'start',
+      maxEdgeStart: 75,
+      threshold: 5,
+      zone: false,
+      domController: domCtrl,
+      gesture: gestureCtlr.createGesture({
+        name: GESTURE_GO_BACK_SWIPE,
+        priority: GESTURE_PRIORITY_GO_BACK_SWIPE,
+        disableScroll: true
+      })
+    });
+  }
+
+  canStart(ev: any): boolean {
+    // the gesture swipe angle must be mainly horizontal and the
+    // gesture distance would be relatively short for a swipe back
+    // and swipe back must be possible on this nav controller
+    return (
+      this._nav.canSwipeBack() &&
+      super.canStart(ev)
+    );
+  }
+
+  onSlideBeforeStart(ev: any) {
+    this._nav.swipeBackStart();
+  }
+
+  onSlide(slide: SlideData, ev: any) {
+    ev.preventDefault();
+    ev.stopPropagation();
+
+    const stepValue = (slide.distance / slide.max);
+    this._nav.swipeBackProgress(stepValue);
+  }
+
+  onSlideEnd(slide: SlideData, ev: any) {
+    const velocity = slide.velocity;
+    const currentStepValue = (slide.distance / slide.max);
+    const isResetDirecction = velocity < 0;
+    const isMovingFast = Math.abs(slide.velocity) > 0.4;
+    const isInResetZone = Math.abs(slide.delta) < Math.abs(slide.max) * 0.5;
+    const shouldComplete = !swipeShouldReset(isResetDirecction, isMovingFast, isInResetZone);
+
+    this._nav.swipeBackEnd(shouldComplete, currentStepValue, velocity);
+  }
+}