Simple Nuxt 3 Page Transition not working - vue.js

Question

I'm discovering Nuxt 3 and and simply want to make an animation between pages. The idea is to use javascript hooks to make page transitions using js library such as gsap or animeJs.
So in my app.vue file, I simply put <NuxtPage/> into <Transition> element like this :
<NuxtLayout>
<Transition>
<NuxtPage/>
</Transition>
</NuxtLayout>
My vue pages ('./pages/index.vue' and './pages/project/myproject.vue') look like this :
<template>
<div>
<h1>My Project</h1>
</div>
</template>
<script setup>
function onEnter(el, done) {
done()
}
function onLeave(el, done) {
done()
}
</script>
I have followed both Nuxt 3 and Vue 3 documentations :
https://v3.nuxtjs.org/guide/directory-structure/pages#layouttransition-and-pagetransition
https://vuejs.org/guide/built-ins/transition.html#javascript-hooks
I also read this thread on github, but I can't find answer :
https://github.com/nuxt/framework/discussions/851
When i was using Nuxt 2 I only need to put transition object into my page like this and it's working fine :
<script>
export default {
// ... (datas, methods)
transition: {
mode: "in-out",
css: false,
enter(el, done) {
console.log("enter");
done()
},
leave(el, done) {
console.log("leave");
done()
}
}
}
</script>
<template>
<div>
<h1 class="text-center text-5xl">Hello World</h1>
</div>
</template>
Do you have any idea how to achieve it ?

Answer 1

Nuxt 3 doesn't need a <Transition> wrapper around pages/layouts, by default it does that for you.
Take a look at this starter template: in assets/sass/app.scss, the last part of the style is page and layout transition.
You can tweak the default named animations (page- and layout-).
More infos here

Answer 2

Just follow the official documentation for Nuxt 3. You need to add the following code to your nuxt.config.ts file:
export default defineNuxtConfig({
app: {
pageTransition: { name: 'page', mode: 'out-in' }
},
})
And then apply the classes inside your app.vue file, like this:
<template>
<NuxtPage />
</template>
<style>
.page-enter-active,
.page-leave-active {
transition: all 0.4s;
}
.page-enter-from,
.page-leave-to {
opacity: 0;
filter: blur(1rem);
}
</style>
Nuxt 3 uses the Vue's <Transition> component under the hood, so you don't need to add it in the template.
Be careful with the css prefix.