Function ɵɵdeferPrefetchWhen

packages/core/src/defer/instructions.ts:268–294

(rawValue: unknown)

 * @codeGenApi
 */
export function ɵɵdeferPrefetchWhen(rawValue: unknown) {
  const lView = getLView();
  const tNode = getSelectedTNode();

  if (ngDevMode) {
    trackTriggerForDebugging(lView[TVIEW], tNode, 'prefetch when <expression>');
  }

  if (!shouldAttachTrigger(TriggerType.Prefetch, lView, tNode)) return;

  const bindingIndex = nextBindingIndex();

  if (bindingUpdated(lView, bindingIndex, rawValue)) {
    const prevConsumer = setActiveConsumer(null);
    try {
      const value = Boolean(rawValue); // handle truthy or falsy values
      const tView = lView[TVIEW];
      const tDetails = getTDeferBlockDetails(tView, tNode);
      if (value === true && tDetails.loadingState === DeferDependenciesLoadingState.NOT_STARTED) {
        // If loading has not been started yet, trigger it now.
        triggerPrefetching(tDetails, lView, tNode);
      }
    } finally {
      setActiveConsumer(prevConsumer);
    }
  }
}

/**
 * Hydrates the deferred content when a value becomes truthy.