Method _observeRenderChanges

src/cdk/table/table.ts:1228–1256

Set up a subscription for the data provided by the data source.

()

  /** Set up a subscription for the data provided by the data source. */
  private _observeRenderChanges() {
    // If no data source has been set, there is nothing to observe for changes.
    if (!this.dataSource) {
      return;
    }

    let dataStream: Observable<readonly T[]> | undefined;

    if (isDataSource(this.dataSource)) {
      dataStream = this.dataSource.connect(this);
    } else if (isObservable(this.dataSource)) {
      dataStream = this.dataSource;
    } else if (Array.isArray(this.dataSource)) {
      dataStream = observableOf(this.dataSource);
    }

    if (dataStream === undefined && (typeof ngDevMode === 'undefined' || ngDevMode)) {
      throw getTableUnknownDataSourceError();
    }

    this._renderChangeSubscription = combineLatest([dataStream!, this.viewChange])
      .pipe(takeUntil(this._onDestroy))
      .subscribe(([data, range]) => {
        this._data = data || [];
        this._renderedRange = range;
        this._dataStream.next(data);
        this.renderRows();
      });
  }

  /**
   * Clears any existing content in the header row outlet and creates a new embedded view