Method _updatePositionInParent

src/material/sidenav/drawer.ts:670–689

* Updates the position of the drawer in the DOM. We need to move the element around ourselves * when it's in the `end` position so that it comes after the content and the visual order * matches the tab order. We also need to be able to move it back to `start` if the sidenav * started off as

(newPosition: 'start' | 'end')

   * started off as `end` and was changed to `start`.
   */
  private _updatePositionInParent(newPosition: 'start' | 'end'): void {
    // Don't move the DOM node around on the server, because it can throw off hydration.
    if (!this._platform.isBrowser) {
      return;
    }

    const element = this._elementRef.nativeElement;
    const parent = element.parentNode!;

    if (newPosition === 'end') {
      if (!this._anchor) {
        this._anchor = this._doc.createComment('mat-drawer-anchor')!;
        parent.insertBefore(this._anchor!, element);
      }

      parent.appendChild(element);
    } else if (this._anchor) {
      this._anchor.parentNode!.insertBefore(element, this._anchor);
    }
  }

  /** Event handler for animation events. */
  private _handleTransitionEvent = (event: TransitionEvent) => {