/vue-skilld

API changes, 3.4 through 3.6.0-beta.17

Citations: official release blog posts and the vuejs/core changelog. For every 3.6 pre-release detail, the source of record is CHANGELOG.md on the minor branch.

3.6 line (through beta.17)

• NEW (experimental): createVaporApp(), createVaporSSRApp(), vaporInteropPlugin, defineVaporComponent(), defineVaporAsyncComponent(), defineVaporCustomElement(), defineVaporSSRCustomElement(), isVaporComponent(), <script setup vapor>. All exported from the main vue entry (dist/vue.d.ts:4-5). See Vapor Mode.
• NEW: renderEffect(), Vapor runtime helpers (delegate, on, createFor, createIf, applyVShow, model appliers), and Vapor built-ins (VaporTransition, VaporKeepAlive, VaporTeleport, VaporSlot); visible in the export list of dist/vue.runtime-with-vapor.esm-browser.prod.js.
• Changed: @vue/reactivity rebuilt on alien-signals; better performance and memory, no API changes (rc.1 notes).
• NEW in beta.11: template compiler resolves slot prop bindings as components (#13573).
• NEW in beta.11: static template hydration fast path (#14752).
• NEW in beta.15: compilerOptions.eventDelegation disables Vapor event delegation (#14924). Removed again in rc.2 in favor of the opt-in .delegate modifier (rc.2 notes).
• Beta.11 to beta.17 otherwise consist of Vapor compiler/runtime stabilization, HMR and custom element fixes (beta.17 entry).

3.5 (release blog)

• NEW useId(): stable SSR/client-unique IDs for forms and accessibility.
• NEW useTemplateRef(key): preferred over name-matched plain refs; supports dynamic ref IDs.
• NEW onWatcherCleanup(fn): cleanup inside watch/watchEffect callbacks; callable from nested functions, unlike the onCleanup parameter.
• NEW lazy hydration: hydrateOnVisible(), hydrateOnIdle(), hydrateOnInteraction(), hydrateOnMediaQuery() passed as defineAsyncComponent({ hydrate }).
• STABLE reactive props destructure: const { count = 0 } = defineProps<{ count?: number }>() replaces withDefaults.
• NEW <Teleport defer>: mounts after the current render cycle so the target can be rendered by the same tree.
• NEW data-allow-mismatch attribute suppresses hydration mismatch warnings.
• NEW useHost() / useShadowRoot() for custom elements.

3.4 (release blog)

• STABLE defineModel(): declares the prop and returns a mutable ref; replaces manual defineProps + emit('update:modelValue').
• NEW v-bind same-name shorthand: :id for :id="id".
• BREAKING: Reactivity Transform ($ref, $computed, $()) removed. Migrate to plain APIs or Vue Macros.
• BREAKING: @vnodeXXX listeners are now a compiler error; use @vue:mounted etc.
• BREAKING: global JSX namespace no longer registered; set jsxImportSource: "vue" or import vue/jsx.
• BREAKING: app.config.unwrapInjectedRef removed; inject() always unwraps refs.
• BREAKING: v-is directive removed; use the special is="vue:Name" prop.
• Perf: watch callbacks now trigger only once per flush, and computed properties trigger effects only when their value reference changes.