What's Nuxt 4's automatic data cleanup mechanism?

Nuxt 4's Singleton Data Fetching Layer implements automatic cleanup by tracking active consumers of each useAsyncData key. When the last component using a specific data ref unmounts, Nuxt automatically removes it from memory, preventing leaks in SPAs.

Code

// Component unmounts → data auto-removed
const { data } = await useAsyncData('user-123', () => $fetch('/api/user'))
// Last consumer unmounts → cache cleared automatically