How to use SSR with Stencil in a Nuxt 3 Vite project? - server-side-rendering

Question

In Nuxt 2 I could use server-side rendered Stencil components by leveraging the renderToString() method provided in the Stencil package in combination with a Nuxt hook, like this:
import { renderToString } from '[my-components]/dist-hydrate'
export default function () {
this.nuxt.hook('generate:page', async (page) => {
const render = await renderToString(page.html, {
prettyHtml: false
})
page.html = render.html
})
}
Since the recent release of Stencil 2.16.0 I'm able to use native web components in Nuxt 3 that is powered by Vite. However I haven't found a way to hook into the template hydration process. Unfortunately there is no documentation for the composable useHydration() yet.
Does anybody know how I could get this to work in Nuxt 3?

Answer 1

I had the same problem. I solved it via a module.
Make a new custom nuxt module. documentation for creating a module
In the setup method hook into the generate:page hook:
nuxt.hook('generate:page', async (page) => {
const render = await renderToString(page.html, {
prettyHtml: true,
});
page.html = render.html;
});
documentation for nuxt hooks
documentation for stencil hydration (renderToString)
Register the css classes you need via nuxt.options.css.push(PATH_TO_CSS)
Register the module in the nuxt config.
Note: Make sure in the nuxt.config.ts the defineNuxtConfig gets exported as default.
Tap the vue compiler options in the nuxt config:
vue: {
compilerOptions: {
isCustomElement: (tag) => TEST_TAG_HERE,
},
},
This depends on how you wan't to use the custom elements. In my case I defined the elements over the stencil loader in my app.vue file:
import { defineCustomElements } from '<package>/<path_to_loader>';
defineCustomElements();
You could also import the elements you need in your component and then define them right there, for example in a example.vue component:
import { CustomElement } from '<package>/custom-elements';
customElements.define('custom-element', CustomElement);
Here is an example from my module and config:
./modules/sdx.ts
import { defineNuxtModule } from '#nuxt/kit';
import { renderToString } from '#swisscom/sdx/hydrate';
export default defineNuxtModule({
meta: {
name: '#nuxt/sdx',
configKey: 'sdx',
},
setup(options, nuxt) {
nuxt.hook('generate:page', async (page) => {
const render = await renderToString(page.html, {
prettyHtml: true,
});
page.html = render.html;
});
nuxt.options.css.push('#swisscom/sdx/dist/css/webcomponents.css');
nuxt.options.css.push('#swisscom/sdx/dist/css/sdx.css');
},
});
Important: This only works if the stenciljs package supports hydration or in other words has a hydrate output. Read more here
./nuxt.config.ts
import { defineNuxtConfig } from 'nuxt';
//v3.nuxtjs.org/api/configuration/nuxt.config export default
export default defineNuxtConfig({
typescript: { shim: false },
vue: {
compilerOptions: {
isCustomElement: (tag) => /sdx-.+/.test(tag),
},
},
modules: ['./modules/sdx'],
});
./app.vue
<template>
<NuxtLayout>
<NuxtPage />
</NuxtLayout>
</template>
<script setup lang="ts">
import { defineCustomElements } from '#swisscom/sdx/dist/js/webcomponents/loader';
defineCustomElements();
// https://v3.nuxtjs.org/guide/features/head-management/
useHead({
title: 'demo',
viewport: 'width=device-width, initial-scale=1, maximum-scale=1',
charset: 'utf-8',
meta: [{ name: 'description', content: 'demo for using a stencil package in a nuxt ssr app' }],
bodyAttrs: {
class: 'sdx',
},
});
</script>
Update
I tested my setup with multiple components and it looks like you cannot define your components in the module. I updated the answer to my working solution.

Answer 2

I've found defining a plugin using the 'render:response' hook to work for me:
server/plugins/ssr-components.plugin.ts
import { renderToString } from '#my-lib/components/hydrate';
export default defineNitroPlugin((nitroApp) => {
nitroApp.hooks.hook('render:response', async (response) => {
response.body = (await renderToString(response.body)).html;
});
});
Perhaps it will work for you :)

Answer 3

Try this in defineNuxtPlugin
nuxtApp.hook('app:rendered', () => {
const response = nuxtApp.ssrContext?.res
if (!response)
return
const end = response.end
response.end = function(chunk) {
chunk = 'hijacked'
end(chunk)
}
})