Method _endDragSequence

src/cdk/drag-drop/drag-ref.ts:835–885

* Clears subscriptions and stops the dragging sequence. * @param event Browser event object that ended the sequence.

(event: MouseEvent | TouchEvent)

   * @param event Browser event object that ended the sequence.
   */
  private _endDragSequence(event: MouseEvent | TouchEvent) {
    // Note that here we use `isDragging` from the service, rather than from `this`.
    // The difference is that the one from the service reflects whether a dragging sequence
    // has been initiated, whereas the one on `this` includes whether the user has passed
    // the minimum dragging threshold.
    if (!this._dragDropRegistry.isDragging(this)) {
      return;
    }

    this._removeListeners();
    this._dragDropRegistry.stopDragging(this);
    this._toggleNativeDragInteractions();

    if (this._handles) {
      (this._rootElement.style as DragCSSStyleDeclaration).webkitTapHighlightColor =
        this._rootElementTapHighlight;
    }

    if (!this._hasStartedDragging()) {
      return;
    }

    this.released.next({source: this, event});

    if (this._dropContainer) {
      // Stop scrolling immediately, instead of waiting for the animation to finish.
      this._dropContainer._stopScrolling();
      this._animatePreviewToPlaceholder().then(() => {
        this._cleanupDragArtifacts(event);
        this._cleanupCachedDimensions();
        this._dragDropRegistry.stopDragging(this);
      });
    } else {
      // Convert the active transform into a passive one. This means that next time
      // the user starts dragging the item, its position will be calculated relatively
      // to the new passive transform.
      this._passiveTransform.x = this._activeTransform.x;
      const pointerPosition = this._getPointerPositionOnPage(event);
      this._passiveTransform.y = this._activeTransform.y;
      this._ngZone.run(() => {
        this.ended.next({
          source: this,
          distance: this._getDragDistance(pointerPosition),
          dropPoint: pointerPosition,
          event,
        });
      });
      this._cleanupCachedDimensions();
      this._dragDropRegistry.stopDragging(this);
    }
  }

  /** Starts the dragging sequence. */
  private _startDragSequence(event: MouseEvent | TouchEvent) {