Type ActionData is `unknown` in TypeScript, but correct in JavaScript in VSCode

[jeppech]

Describe the bug

It seems that there's a bug, when inferring types from the new actions export (recently merged #6469), in the +page.server.ts files.

I'm using the Svelte for VS Code v105.22.1 extension.

In short, the ActionData type is not inferred correctly in TypeScript projects. But it is in JavaScript projects.

// +page.server.svelte
import type { Actions } from './$types'

export const actions: Actions = {
  default: ({ request }) => {
    return {
      horse: true
    }
  }
}

// +page.svelte
<script lang="ts">
  import type { PageData, ActionData } from './$types'

  export let data: PageData

  // ActionData is of unknown type
  export let form: ActionData
</script>

Reproduction

The issue can be tested with this project https://github.com/jeppech/svelte-action-data-ts-bug

• git clone https://github.com/jeppech/svelte-action-data-ts-bug
• Go to the js folder, install dependencies and run the dev script. cd js && pnpm install && pnpm run dev
• Go to the ts folder, install dependencies and run the dev script. cd ts && pnpm install && pnpm run dev

Open the js and ts folder, in their own instance of VSCode.

In the JavaScript project src/routes/+page.svelte: The ActionData-type has a horse property, which is correctly inferred from the +page.server.js file

In the TypeScript project src/routes/+page.svelte: The ActionData-type is unknown, so it's not being inferred correctly from the +page.server.ts file

Logs

No response

System Info

❯ pnpx envinfo --system --binaries --browsers --npmPackages "{svelte,@sveltejs/*,vite}"
.../../.node/pnpm/store/v3/tmp/dlx-65331 |   +1 +
Packages are hard linked from the content-addressable store to the virtual store.
  Content-addressable store is at: /Users/jc/.node/pnpm/store/v3
  Virtual store is at:             ../../../.node/pnpm/store/v3/tmp/dlx-65331/node_modules/.pnpm
.../../.node/pnpm/store/v3/tmp/dlx-65331 | Progress: resolved 1, reused 0, downloaded 1, added 1, done

  System:
    OS: macOS 12.4
    CPU: (8) arm64 Apple M1 Pro
    Memory: 1.13 GB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 16.17.0 - ~/Library/pnpm/node
    npm: 8.15.0 - ~/Library/pnpm/npm
  Browsers:
    Brave Browser: 105.1.43.89
    Safari: 15.5
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.71
    @sveltejs/kit: next => 1.0.0-next.477
    svelte: ^3.44.0 => 3.50.0
    vite: ^3.1.0 => 3.1.0

Severity

blocking an upgrade

Additional Information

No response

[aloker]

I'm seeing this, too, but the issue is probably a duplicate of #6631, right?

[jeppech]

I'm seeing this, too, but the issue is probably a duplicate of #6631, right?

You're right, I did not spot that when searching the issue list. I'll close this. Thanks! 😀