Function mutateChildren

src/cdk/tree/tree.spec.ts:1117–1131

(parent: TestData)

      }

      function mutateChildren(parent: TestData) {
        // Swap first and second data in data array
        const copiedData = parent.children.slice();
        const temp = copiedData[0];
        copiedData[0] = copiedData[1];
        copiedData[1] = temp;

        // Remove the third element
        copiedData.splice(2, 1);

        // Add new data
        parent.children = copiedData;
        parent.observableChildren.next(copiedData);
        component.dataSource.addChild(parent, false);
      }

      it('should add/remove/move children nodes with reference-based trackBy', () => {
        createTrackByTestComponent('reference');