Method withBoundaryElement

src/cdk/drag-drop/drag-ref.ts:520–529

* Element to which the draggable's position will be constrained.

(boundaryElement: ElementRef<HTMLElement> | HTMLElement | null)

   * Element to which the draggable's position will be constrained.
   */
  withBoundaryElement(boundaryElement: ElementRef<HTMLElement> | HTMLElement | null): this {
    this._boundaryElement = boundaryElement ? coerceElement(boundaryElement) : null;
    this._resizeSubscription.unsubscribe();
    if (boundaryElement) {
      this._resizeSubscription = this._viewportRuler
        .change(10)
        .subscribe(() => this._containInsideBoundaryOnResize());
    }
    return this;
  }

  /** Sets the parent ref that the ref is nested in.  */
  withParent(parent: DragRef<unknown> | null): this {