Function scheduleDelayedTrigger

packages/core/src/defer/triggering.ts:78–99

(
  scheduleFn: (callback: VoidFunction, injector: Injector) => VoidFunction,
)

 * Schedules triggering of a defer block for `on idle` and `on timer` conditions.
 */
export function scheduleDelayedTrigger(
  scheduleFn: (callback: VoidFunction, injector: Injector) => VoidFunction,
) {
  const lView = getLView();
  const tNode = getCurrentTNode()!;

  renderPlaceholder(lView, tNode);

  // Exit early to avoid invoking `scheduleFn`, which would
  // add `setTimeout` call and potentially delay serialization
  // on the server unnecessarily.
  if (!shouldTriggerDeferBlock(TriggerType.Regular, lView)) return;

  const injector = lView[INJECTOR];
  const lDetails = getLDeferBlockDetails(lView, tNode);

  const cleanupFn = scheduleFn(
    () => triggerDeferBlock(TriggerType.Regular, lView, tNode),
    injector,
  );
  storeTriggerCleanupFn(TriggerType.Regular, lDetails, cleanupFn);
}

/**
 * Schedules prefetching for `on idle` and `on timer` triggers.