KeepAlive component là gì?

<KeepAlive> cache component instance khi unmount — state được giữ nguyên khi switch lại:

<KeepAlive :include="['FormStep1', 'FormStep2']" :max="5">
  <component :is="currentTab" />
</KeepAlive>

• Lifecycle hooks cho cached components: onActivated (khi cache hit, component show lại), onDeactivated (khi bị hide, không unmount).
• Dùng cho: tab views, multi-step forms, expensive components cần giữ state.
• Lưu ý: cached components vẫn chiếm bộ nhớ — dùng :max để limit, tránh cache tất cả.

<KeepAlive> caches component instances when unmounted — state is preserved when switching back:

<KeepAlive :include="['FormStep1', 'FormStep2']" :max="5">
  <component :is="currentTab" />
</KeepAlive>

• Lifecycle hooks for cached components: onActivated (on cache hit, component shown again), onDeactivated (when hidden, not unmounted).
• Use for: tab views, multi-step forms, expensive components needing state preservation.

Pitfall: cached components still consume memory — use :max to limit, avoid caching everything.