Vue 3 Composition API

Quick Guide: <script setup> for every component. ref() for primitives and anything reassigned, reactive() for an object mutated in place. Reusable stateful logic goes into a use* composable that returns an object of refs. Everything opened in onMounted is closed in onUnmounted. The 3.4+ and 3.5+ macros — defineModel(), useTemplateRef(), useId(), onWatcherCleanup() — replace whole patterns that preceded them, and destructured props need a getter wrapper in watch().

Detailed Resources:

• examples/core.md — a complete component, template refs, focus management
• examples/reactivity.md — ref, reactive, computed and their anti-patterns
• examples/composables.md — useFetch, useLocalStorage, useDebounce, useIntersectionObserver
• examples/lifecycle.md — WebSockets, timers, event listeners, cleanup
• examples/provide-inject.md — theme provider, typed injection keys
• examples/define-expose.md — form field validation, parent-child coordination
• examples/vue-3-5-features.md — defineModel, useTemplateRef, useId, onWatcherCleanup, reactive destructure, deferred Teleport
• examples/async.md — lazy loading, Suspense, async setup
• reference.md — decision trees, anti-patterns with corrected code, checklists, TypeScript patterns

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