Function applyDeferBlockState

packages/core/src/defer/rendering.ts:238–317

* Applies changes to the DOM to reflect a given state.

(
  newState: DeferBlockState,
  lDetails: LDeferBlockDetails,
  lContainer: LContainer,
  tNode: TNode,
  hostLView: LView<unknown>,
)

 * Applies changes to the DOM to reflect a given state.
 */
function applyDeferBlockState(
  newState: DeferBlockState,
  lDetails: LDeferBlockDetails,
  lContainer: LContainer,
  tNode: TNode,
  hostLView: LView<unknown>,
) {
  profiler(ProfilerEvent.DeferBlockStateStart);

  const stateTmplIndex = getTemplateIndexForState(newState, hostLView, tNode);

  if (stateTmplIndex !== null) {
    lDetails[DEFER_BLOCK_STATE] = newState;
    const hostTView = hostLView[TVIEW];
    const adjustedIndex = stateTmplIndex + HEADER_OFFSET;

    // The TNode that represents a template that will activated in the defer block
    const activeBlockTNode = getTNode(hostTView, adjustedIndex) as TContainerNode;

    // There is only 1 view that can be present in an LContainer that
    // represents a defer block, so always refer to the first one.
    const viewIndex = 0;

    removeLViewFromLContainer(lContainer, viewIndex);

    let injector: Injector | undefined;
    if (newState === DeferBlockState.Complete) {
      // When we render a defer block in completed state, there might be
      // newly loaded standalone components used within the block, which may
      // import NgModules with providers. In order to make those providers
      // available for components declared in that NgModule, we create an instance
      // of an environment injector to host those providers and pass this injector
      // to the logic that creates a view.
      const tDetails = getTDeferBlockDetails(hostTView, tNode);
      const providers = tDetails.providers;
      if (providers && providers.length > 0) {
        injector = createDeferBlockInjector(hostLView[INJECTOR], tDetails, providers);
      }
    }
    const {dehydratedView, dehydratedViewIx} = findMatchingDehydratedViewForDeferBlock(
      lContainer,
      lDetails,
    );

    const embeddedLView = createAndRenderEmbeddedLView(hostLView, activeBlockTNode, null, {
      injector,
      dehydratedView,
    });
    addLViewToLContainer(
      lContainer,
      embeddedLView,
      viewIndex,
      shouldAddViewToDom(activeBlockTNode, dehydratedView),
    );
    markViewForRefresh(embeddedLView);

    if (dehydratedViewIx > -1) {
      // Erase dehydrated view info in a given LContainer, so that the view is not