[labs/ssr] Deno Support

Should this be an RFC?

• This is not a substantial change

Which package is this a feature request for?

SSR (@lit-labs/ssr)

Description

I’m trying to use Lit.js SSR in the Astro framework with the Deno SSR engine, but Lit.js SSR currently depends on require()s of Node.js-only modules which do not work in Deno.

I know SSR is work-in-progress anyway, but it would be great to have a way to use Lit’s SSR on a Deno server.

Alternatives and Workarounds

I may have to try switching to Node.js instead of Deno, but Deno is preferred for my project due to it’s ability to deploy to Deno Deploy’s hosted service.

[kevinpschaaf]

So it sounds like the problem isn’t actually that lit-ssr is depending on commonjs modules, it’s that we’re depending on built-in node modules?

We don’t do this much fwict, other than createRequire in parse5-utils, and transitively via node-fetch in the DOM shim (excluding the VM-based entry points, which wouldn’t be in scope for Deno usage anyway).

Once we upgrade to the new esm parse5 and can rely on node’s built-in fetch in the dom-shim, seems like this might fix itself?

[mhoad]

I would switch to Deno in a heartbeat if you ended up making those changes. Would simplify the DX by quite a bit.