Function createTestComponentWithTrackyByTable

src/cdk/table/table.spec.ts:1738–1757

(trackByStrategy: string)

  describe('with trackBy', () => {
    function createTestComponentWithTrackyByTable(trackByStrategy: string) {
      fixture = TestBed.createComponent(TrackByCdkTableApp);

      component = fixture.componentInstance;
      component.trackByStrategy = trackByStrategy;

      tableElement = fixture.nativeElement.querySelector('cdk-table');
      fixture.detectChanges();

      // Each row receives an attribute 'initialIndex' the element's original place
      getRows(tableElement).forEach((row: Element, index: number) => {
        row.setAttribute('initialIndex', index.toString());
      });

      // Prove that the attributes match their indicies
      const initialRows = getRows(tableElement);
      expect(initialRows[0].getAttribute('initialIndex')).toBe('0');
      expect(initialRows[1].getAttribute('initialIndex')).toBe('1');
      expect(initialRows[2].getAttribute('initialIndex')).toBe('2');
    }

    // Swap first two elements, remove the third, add new data
    function mutateData() {