Cannot use MongoDB

[emilkrebs]

Hey,

I am trying to use MongoDB using the new Fresh 2.0 and Vite. However, as soon as I call new MongoClient(uri) it fails, throwing [vite] (ssr) Error when evaluating SSR module fresh:server_entry: (0 , resource_management_1.configureResourceManagement) is not a function.
It doesn't matter if I call it from a middleware, component, or everywhere else; the error persists.

Let me know if you need more context!

My dependencies:

"imports": {
		"fresh": "jsr:@fresh/core@^2.0.0-beta.4",
		"preact": "npm:preact@^10.27.1",
		"@preact/signals": "npm:@preact/signals@^2.3.1",
		"@fresh/plugin-vite": "jsr:@fresh/plugin-vite@^0.9.13",
		"vite": "npm:vite@^7.1.3",
		"tailwindcss": "npm:tailwindcss@^4.1.10",
		"@tailwindcss/vite": "npm:@tailwindcss/vite@^4.1.12",
		"@deno/gfm": "jsr:@deno/gfm@^0.11.0",
		"@valibot/valibot": "jsr:@valibot/valibot@^1.1.0",
		"$std/": "https://deno.land/std@0.216.0/",
		"mongodb": "npm:mongodb@6.19.0",
		"bcrypt": "https://deno.land/x/bcrypt@v0.4.1/mod.ts"
	},

How to reproduce:

• add npm:mongodb
• call new MongoClient() in the project

Example

...
// Pass a shared value from a middleware
app.use(async (ctx) => {
  ctx.state.shared = "hello";
  const client = new MongoClient("mongodb://127.0.0.1:27017");
  return await ctx.next();
});
...

[lunadogbot]

This looks like the same family of CJS interop bugs as #3673 and #3480: an npm package (mongodb) does CJS-style namespace imports (resource_management_1.configureResourceManagement) that lose their named exports when the package is bundled through Vite's SSR pipeline rather than externalized.

PR #3765 (fix: externalize CJS-only npm packages in SSR build) should fix this once merged — it leaves CJS-only packages to be required at runtime instead of pre-bundled, which preserves the namespace shape MongoDB expects.

Workaround for now: add mongodb to ssr.external in your Vite config, e.g.:

export default defineConfig({
  ssr: {
    external: ["mongodb"],
  },
  plugins: [fresh()],
});