Package now compiles Typescript files to CJS instead of ESM

[jacob-8]

Describe the bug

Upgrading from @sveltejs/kit@1.0.0-next.314 to @sveltejs/kit@1.0.0-next.315 will change the output of svelte-kit package as follows:

My package is now broken when trying to install in another app (ReferenceError: exports is not defined in reference to an action defined in a .js file) if I upgrade SvelteKit and I'm forced to stay .314.

Reproduction

• Clone https://github.com/jacob-8/svelte-pieces/
• pnpm i
• pnpm package - look at any compiled .js filed inside /package
• update to @sveltejs/kit@1.0.0-next.315 or higher
• pnpm i
• pnpm package and inspect different results in compiled .js files in /package

Logs

No response

System Info

System:
    OS: Windows 10 10.0.22000
    CPU: (8) x64 Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz
    Memory: 1.14 GB / 11.77 GB
  Binaries:
    Node: 16.13.2 - C:\Program Files\nodejs\node.EXE
    npm: 8.1.4 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Spartan (44.22000.120.0), Chromium (100.0.1185.50)
    Internet Explorer: 11.0.22000.120
  npmPackages:
    @sveltejs/adapter-auto: 1.0.0-next.40 => 1.0.0-next.40
    @sveltejs/kit: 1.0.0-next.314 => 1.0.0-next.315
    @sveltejs/vite-plugin-svelte: ^1.0.0-next.41 => 1.0.0-next.41
    svelte: ^3.47.0 => 3.47.0

Severity

blocking an upgrade

Additional Information

No response

[elliott-with-the-longest-name-on-github]

Weird... I just checked the changelog for 314 => 315, and this is the only line I could possibly see that might cause this issue, but it shouldn't be the problem. I'll try to look further into this when I get home to at least triage.

[dummdidumm]

Possibly related #4460

[gtm-nayan]

This commit seems like the culprit, changelog didn't pick up on it 2bb2ab0

[gtm-nayan]

Oh, it's a create-svelte change, that's why

[dummdidumm]

Thanks @gtm-nayan that might be indeed the culprit. If you set target and lib to what was generated before, does the error go away?

		"lib": ["es2020", "DOM"],
		"moduleResolution": "node",
		"module": "es2020",
		"resolveJsonModule": true,
		"skipLibCheck": true,
		"sourceMap": true,
		"strict": true,
		"target": "es2020"

[jacob-8]

Thank you, all! I created a new svelte-kit app and copied in the default compilerOptions from the j/tsconfig.json file and all is working as expected using this tsconfig:

I know it's not 1.0, but it'd be nice for that to be documented somewhere as breaking change. I had already scoured the docs and changelogs ahead of posting my bug but it wasn't there of course.