default to target: node14.8

[Rich-Harris]

Fixes #1538, where I recommended that people do async setup work in src/hooks.js (or any other module, really) using top-level await. This works wonderfully in development, but it turns out svelte-kit build fails because Vite runs everything through esbuild (not sure why, if I'm perfectly honest, but that's a separate conversation) and we currently use target: 'es2020' which doesn't allow top-level await:

chunks/hooks-4fb5bb73.js:206:0: ERROR: Top-level await is not available in the configured target environment ("es2020")

This changes it to node16. I tried node14 at first, but that still didn't work even though top-level await definitely is supported there. I think this is probably fine, and at any rate, you can override it in config.kit.vite.build.target.

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[bluwy]

Vite runs everything through esbuild

It's using esbuild in the renderChunk() phase for minification. (source)

I tried node14 at first, but that still didn't work even though top-level await definitely is supported there

esbuild keeps a compat table for top level await. It only exists in 14.8, so specifying node14.8 should work too.

[Rich-Harris]

specifying node14.8 should work too

nice, it does

[bluwy]

Looks like the package.json have "node": ">=14.13" so we should be safe with the change too.

[digitaldeus]

Hi is it possible to add this to the vercel adapter as well? Building to vercel still fails with top-level await errors and looks like that adapter is set to node14