Reproduction: HTMLElement is not defined with nuxt-ssr-lit and @material/web

This repository reproduces an issue where a 500 HTMLElement is not defined error occurs on page load in a built Nuxt environment when using nuxt-ssr-lit with @material/web components.

Problem

In a production-like build environment (e.g., after running bun run build && bun run preview or when deployed to Cloudflare Pages), attempting to load a page that utilizes @material/web components results in a server-side error: 500 HTMLElement is not defined.

Environment & Dependencies

Category	Item	Version
OS	macOS	15.6.1
Browser	Google Chrome	140.0.7339.81
Node.js	Node.js	24.7.0
Bun	Bun	1.2.21
Framework	Nuxt	4.1.0
UI Library	@material/web	2.4.0
SSR Helper	nuxt-ssr-lit	1.6.32

Deployment Target

Cloudflare Pages

Steps to Reproduce

1. Clone this repository:

git clone git@github.com:cotone-dev/nuxt-ssr-lit-material-web-repro.git
cd nuxt-ssr-lit-material-web-repro

2. Install dependencies:

bun i

3. Build and preview the application:

bun run build && bun run preview

4. Access the preview page: When prompted by the preview server:

[b] open a browser, [d] open devtools, [c] clear console, [x] to exit

Press b to open the page in your browser.

5. Observe the 500 error: The page will display: "500 HTMLElement is not defined".

Error Object Contents:

{
  "error": true,
  "message": "HTMLElement is not defined",
  "statusCode": 500,
  "statusMessage": "Server Error",
  "url": "/"
}

Wrangler Log (or similar server log for bun run preview):

[wrangler:inf] GET / 500 Server Error (233ms)

(Note: The log might vary slightly depending on the preview server, but the 500 error related to HTMLElement should be present.)

What I've Tried

• Adding '@material/web' to nitro.moduleSideEffects in nuxt.config.ts. This did not resolve the issue.

// nuxt.config.ts
export default defineNuxtConfig({
  // ...
  nitro: {
    moduleSideEffects: ['@material/web'],
  },
  // ...
});

Expected Behavior

@material/web components should be usable in a Nuxt SSR environment without throwing an HTMLElement is not defined error during server-side rendering. The page should render correctly.