bug: ESM not supported in Node.js 14 environment

[jthegedus]

Describe the bug

Node.js 14 Google Cloud Function environment does not support ESM yet - GoogleCloudPlatform/functions-framework-nodejs#233

This support is required for Firebase Cloud Functions and if we want to use the same handler.js here for both Cloud Run and Cloud Functions.

Since the Vite SSR app.js file imports @sveltejs/kit/renderer via ESM import, and the @sveltejs/kit lib only outputs ESM, we cannot use SvelteKit in Cloud Functions.

Work arounds

Until this is supported, we have a some options:

1. run the Vite SSR app.js file through Rollup and bundle/compile/transpile/transform the deps
2. Deprecate Cloud Function support until this is resolved AND migrate Cloud Run support away from Functions Framework so we can recommend that approach in the meantime

I am likely going to go with 2. for now.

[jthegedus]

Tracking these issues as potential solutions:

• Netlify and Vercel lambda functions expect CJS, not ESM sveltejs/kit#400
• Create CJS build output, or expect adapters to bundle the ESM themselves? sveltejs/kit#503 < more important!

Hopefully we can just configure SvelteKit to output CJS for SSR 🤞

[jthegedus]

It seems there was a workaround to this issue which is currently working in 0.5.0 for Cloud Run in 0.4.1 and Cloud Functions in #21

This workaround was lifted from the official adapters like adapter-vercel and co.

[jthegedus]

#39 uses https://esbuild.github.io/ to compile to commonjs working around this issue