Function renderDeferBlockState

packages/core/src/defer/rendering.ts:164–220

(
  newState: DeferBlockState,
  tNode: TNode,
  lContainer: LContainer,
  skipTimerScheduling = false,
)

 *   between states via `DeferFixture.render` method.
 */
export function renderDeferBlockState(
  newState: DeferBlockState,
  tNode: TNode,
  lContainer: LContainer,
  skipTimerScheduling = false,
): void {
  const hostLView = lContainer[PARENT];
  const hostTView = hostLView[TVIEW];

  // Check if this view is not destroyed. Since the loading process was async,
  // the view might end up being destroyed by the time rendering happens.
  if (isDestroyed(hostLView)) return;

  // Make sure this TNode belongs to TView that represents host LView.
  ngDevMode && assertTNodeForLView(tNode, hostLView);

  const lDetails = getLDeferBlockDetails(hostLView, tNode);

  ngDevMode && assertDefined(lDetails, 'Expected a defer block state defined');

  const currentState = lDetails[DEFER_BLOCK_STATE];

  const ssrState = lDetails[SSR_BLOCK_STATE];
  if (ssrState !== null && newState < ssrState) {
    return; // trying to render a previous state, exit
  }

  if (
    isValidStateChange(currentState, newState) &&
    isValidStateChange(lDetails[NEXT_DEFER_BLOCK_STATE] ?? -1, newState)
  ) {
    const tDetails = getTDeferBlockDetails(hostTView, tNode);
    // Skips scheduling on the server since it can delay the server response.
    const needsScheduling =
      !skipTimerScheduling &&
      (typeof ngServerMode === 'undefined' || !ngServerMode) &&
      (getLoadingBlockAfter(tDetails) !== null ||
        getMinimumDurationForState(tDetails, DeferBlockState.Loading) !== null ||
        getMinimumDurationForState(tDetails, DeferBlockState.Placeholder));

    if (ngDevMode && needsScheduling) {
      assertDefined(
        applyDeferBlockStateWithSchedulingImpl,
        'Expected scheduling function to be defined',
      );
    }

    const applyStateFn = needsScheduling
      ? applyDeferBlockStateWithSchedulingImpl!
      : applyDeferBlockState;
    try {
      applyStateFn(newState, lDetails, lContainer, tNode, hostLView);
    } catch (error: unknown) {
      handleUncaughtError(hostLView, error);
    }
  }
}