[BUG] app-template-svelte-typescript fails to compile App.svelte if unrelated test import is removed

[frederikhors]

Bug Report Quick Checklist

• I am on the latest version of Snowpack & all plugins.
• I use package manager npm
• I run Snowpack on OS Windows 10
• I run Snowpack on Node.js v14

Describe the bug

I've come across a problem where the application code no longer compiles when a test library import is removed from a seemingly unrelated file.

To Reproduce

From #2472:

# Create project with the template
npx create-snowpack-app theapp --template @snowpack/app-template-svelte-typescript

# Enter the project
cd theapp

# Verify that the project works
npm start # This succeeds

# Remove the test file
rm src/App.test.ts

# Now the project fails to build citing an unrelated file not being found
npm start

In this example I've removed the entire file, but it is enough to remove or comment out just this line:
https://github.com/snowpackjs/snowpack/blob/0f9d34b8cf747e33524b31920d5610f6403c5480/create-snowpack-app/app-template-svelte/src/App.test.js#L1

Expected behavior

It should work.

Anything else?

@thisislawatts found a solution: #2472 (comment)

@lpil suggested:

it looks like we may need to add the npm i --save-dev @tsconfig/svelte dep and add "extends": "@tsconfig/svelte/tsconfig.json", to .tsconfig.json for that template.

[frederikhors]

After adding @tsconfig/svelte now I have another error in my index.ts file:

Property 'hot' does not exist on type 'ImportMeta'.ts(2339).

😭

UPDATE: I can fix it using #1433 (comment).

[drwpow]

This has been fixed in the latest patch of @snowpack/app-template-svelte-typescript! Thanks for opening

[lpil]

Thank you!