Set target to es2019 in default tsconfig.json

[benmccann]

Should at least make it 2020. Someone on Discord ran into an issue with it being an older version

I hadn't set it in jsconfig.json because that file is pretty minimal and doesn't have any of the other tsconfig.json contents. I'm not sure which settings go in both vs just one or the other

[GrygrFlzr]

Just tested, looks like jsconfig doesn't need it, yeah.

[dummdidumm]

Jsconfig doesn't need it because it's not used for bundling afaik. For tsconfig that's a different story though. Which problem was it? My fear is that transformations from ts to js might leave stuff in that is too new for anything besides Chrome.

[GrygrFlzr]

Vite can further transform the output though, can't it? There's even plugins to do ES5, if I remember correctly. TS -> JS is not the final output, I think?

[dummdidumm]

Honestly I don't know 😄 all I know for sure is that this setting will produce different output for the generated code inside Svelte script tags, because the preprocessors use the tsconfig. If it gets downleveld afterwards (js->older js) I don't know.

[GrygrFlzr]

We also need to update .eslintrc.cjs to use parserOptions.ecmaVersion 2020 or it'll complain on linting:

  7:17  error  Parsing error: Unexpected token import

✖ 1 problem (1 error, 0 warnings)

[Conduitry]

@lukeed might have something to say about this. I believe there was a reason we're targeting this version, and it may have to do with what's available in current lambda environments.

[GrygrFlzr]

Of the existing adapters, Vercel and Netlify has access to Node 14, and Begin has Node 12. Cloudflare Workers is running some version of v8.

If you are targeting Node.js 12.9.0 or newer, you can simply specify "lib": ["es2020"] as that version supports all new functions and properties introduced in ES2020. It doesn't support the new JavaScript syntax though, so you still have to stay on "target": "es2019".

- Linus Unnebäck from stackoverflow

We're targeting 12.17+ due to ESM, so looks like we can instead do:

{
  "compilerOptions": {
    "moduleResolution": "node",
    "lib": ["es2020"],
    "target": "es2019",

That said I ironically cannot replicate import.meta.glob / import.meta.env being an issue on the TypeScript template, and can only make it fail on ESLint on the JS template.

[lukeed]

I think es2019 is the latest value you can use while still working in most places. Something like ?? is left as-is with esnext, but that breaks in Node 14.x runtimes.

[benmccann]

ok, i've bumped it to 2019 for now