Function triggerDeferBlock

packages/core/src/defer/triggering.ts:320–362

(triggerType: TriggerType, lView: LView, tNode: TNode)

 * no additional actions are taken.
 */
export function triggerDeferBlock(triggerType: TriggerType, lView: LView, tNode: TNode) {
  const tView = lView[TVIEW];
  const lContainer = lView[tNode.index];
  ngDevMode && assertLContainer(lContainer);

  if (!shouldTriggerDeferBlock(triggerType, lView)) return;

  const lDetails = getLDeferBlockDetails(lView, tNode);
  const tDetails = getTDeferBlockDetails(tView, tNode);

  // Defer block is triggered, cleanup all registered trigger functions.
  invokeAllTriggerCleanupFns(lDetails);

  switch (tDetails.loadingState) {
    case DeferDependenciesLoadingState.NOT_STARTED:
      renderDeferBlockState(DeferBlockState.Loading, tNode, lContainer);
      triggerResourceLoading(tDetails, lView, tNode);

      // The `loadingState` might have changed to "loading".
      if (
        (tDetails.loadingState as DeferDependenciesLoadingState) ===
        DeferDependenciesLoadingState.IN_PROGRESS
      ) {
        renderDeferStateAfterResourceLoading(tDetails, tNode, lContainer);
      }
      break;
    case DeferDependenciesLoadingState.IN_PROGRESS:
      renderDeferBlockState(DeferBlockState.Loading, tNode, lContainer);
      renderDeferStateAfterResourceLoading(tDetails, tNode, lContainer);
      break;
    case DeferDependenciesLoadingState.COMPLETE:
      ngDevMode && assertDeferredDependenciesLoaded(tDetails);
      renderDeferBlockState(DeferBlockState.Complete, tNode, lContainer);
      break;
    case DeferDependenciesLoadingState.FAILED:
      renderDeferBlockState(DeferBlockState.Error, tNode, lContainer);
      break;
    default:
      if (ngDevMode) {
        throwError('Unknown defer block state');
      }
  }
}

/**
 * The core mechanism for incremental hydration. This triggers or