Function ɵɵdeferOnHover

packages/core/src/defer/instructions.ts:567–595

(triggerIndex: number, walkUpTimes?: number)

 * @codeGenApi
 */
export function ɵɵdeferOnHover(triggerIndex: number, walkUpTimes?: number) {
  const lView = getLView();
  const tNode = getCurrentTNode()!;

  if (ngDevMode) {
    trackTriggerForDebugging(
      lView[TVIEW],
      tNode,
      `on hover${walkUpTimes === -1 ? '' : '(<target>)'}`,
    );
  }

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

  renderPlaceholder(lView, tNode);

  // Avoid adding event listeners when this instruction is invoked on the server.
  if (!(typeof ngServerMode !== 'undefined' && ngServerMode)) {
    registerDomTrigger(
      lView,
      tNode,
      triggerIndex,
      walkUpTimes,
      onHover,
      () => triggerDeferBlock(TriggerType.Regular, lView, tNode),
      TriggerType.Regular,
    );
  }
}

/**
 * Creates runtime data structures for the `prefetch on hover` deferred trigger.