Method _changeDataSource

src/cdk/scrolling/virtual-for-of.ts:299–309

Swap out one `DataSource` for another.

(
    oldDs: DataSource<T> | null,
    newDs: DataSource<T> | null,
  )

  /** Swap out one `DataSource` for another. */
  private _changeDataSource(
    oldDs: DataSource<T> | null,
    newDs: DataSource<T> | null,
  ): Observable<readonly T[]> {
    if (oldDs) {
      oldDs.disconnect(this);
    }

    this._needsUpdate = true;
    return newDs ? newDs.connect(this) : observableOf();
  }

  /** Update the `CdkVirtualForOfContext` for all views. */
  private _updateContext() {