vue 3.6.0-beta.17 (vuejs/core)

Pre-release beta of the 3.6 line. Two headline changes vs 3.5:

• Vapor Mode, an opt-in compilation strategy for SFCs that skips the Virtual DOM; see Vapor Mode.
• alien-signals reactivity refactor: @vue/reactivity was rebuilt on alien-signals for lower memory use and faster updates. No public API changes.

Package facts (from the prepared source):

• Version: package.json:3.
• The main entry re-exports @vue/runtime-dom AND @vue/runtime-vapor, so all Vapor APIs (createVaporApp, vaporInteropPlugin, defineVaporComponent) import from plain vue: dist/vue.d.ts:4-5.
• Named exports added by the vue package itself: compile, defineVaporAsyncComponent, withAsyncContext: dist/vue.runtime.esm-bundler.js:12.
• Subpath exports: vue/server-renderer, vue/compiler-sfc, vue/jsx-runtime, vue/jsx: package.json:36-68.
• TypeScript is an optional peer dependency (*): package.json:107-113.

Common tasks

Component with <script setup>, reactive props destructure, and defineModel:

<script setup lang="ts">
const { count = 0 } = defineProps<{ count?: number }>()
const model = defineModel<string>({ default: '' })
</script>

<template>
  <input v-model="model" />
  <p>{{ count }}</p>
</template>

Template refs (3.5+ pattern):

import { useTemplateRef } from 'vue'
const input = useTemplateRef('my-input') // matches ref="my-input" in template

Watch with cleanup (3.5+):

import { watch, onWatcherCleanup } from 'vue'
watch(id, () => {
  const controller = new AbortController()
  load(id.value, controller)
  onWatcherCleanup(() => controller.abort())
})

Composable that accepts a value, ref, or getter:

import { toValue, type MaybeRefOrGetter } from 'vue'
function useDouble(source: MaybeRefOrGetter<number>) {
  return computed(() => toValue(source) * 2)
}

Lazy hydration for SSR (3.5+):

import { defineAsyncComponent, hydrateOnVisible } from 'vue'
const Heavy = defineAsyncComponent({
  loader: () => import('./Heavy.vue'),
  hydrate: hydrateOnVisible(),
})

Version rules that change what you write

Full list with citations in API changes. The ones that break old code:

• Reactivity Transform ($ref, $computed) was removed in 3.4. Use plain ref/computed, or the Vue Macros plugin.
• @vnodeXXX listeners are a compiler error since 3.4. Use @vue:mounted style listeners.
• Global JSX namespace is no longer registered since 3.4. Set jsxImportSource: "vue" in tsconfig, or import vue/jsx.
• In Vapor components (3.6), Options API, app.config.globalProperties, getCurrentInstance(), v-memo, and @vue:xxx element lifecycle events do not work.
• Vapor event delegation is on by default in beta.17: stopPropagation() in an ancestor can cancel delegated handlers. Disable per build with compilerOptions.eventDelegation (added in beta.15, #14924). Note: rc.2 replaced this with an opt-in .delegate modifier (release notes).

Bundler and dist notes

• Bundlers resolve the runtime-only build; templates in .vue files are pre-compiled. For runtime template compilation (in-DOM templates or template strings), alias vue to vue/dist/vue.esm-bundler.js.
• Replace __VUE_OPTIONS_API__, __VUE_PROD_DEVTOOLS__, __VUE_PROD_HYDRATION_MISMATCH_DETAILS__ at build time for correct tree-shaking (compile-time flags).
• In Node CJS, importing vue/compiler-sfc auto-registers TypeScript via registerTS(() => require('typescript')) when resolvable: compiler-sfc/register-ts.js:1-3.

Details, dist-file selection, and the export catalog: API surface.

References

• API surface: entry points, dist builds, feature flags, export catalog.
• Vapor Mode: opt-in, interop, constraints, directives, event delegation.
• API changes 3.4 to 3.6: new, stable, and removed APIs per version, with citations.
• Best practices: composable and performance patterns proven against the official docs.