Error: Could not resolve TypeScript file without .ts extension

[hbbio]

Describe the bug

When using Svelte with an external script, in TypeScript, which itself imports components from other .ts files, we can't omit the .ts extension for import.

Otherwise, build fails with:

src/main.ts → public/build/bundle.js...
[!] Error: Could not resolve './initials' from src/App.svelte

Note that adding the .ts extension solves the problem with svelte-preprocess but then raises the following TypeScript error:

src/main.ts → public/build/bundle.js...
src/App.svelte:1:26 - error TS2691: An import path cannot end with a '.ts' extension. Consider importing './initials' instead.

To Reproduce

Cf. hbbio/svelte-ts@4ae0dd0

Expected behavior
Ability to import TypeScript files without the ts extension.
Information about your project:

• svelte 3.23.0
• typescript 3.9.3
• svelte-preprocess 3.7.4
• rollup

[hbbio]

The temporary fix to add the .ts extension (despite ts error) does not work if the imported file is in a different directory: It tries to resolve the file using the path of the .svelte component.

[kaisermann]

Fixed in v4 as we're now only transpiling ts to js. Import resolution should be configured from the bundle side 😁 .

[MALIK-0]

@kaisermann I'm using svelte-preprocess (4.1.1) and svelte (3.17.3) and face the same issue.

routes/index.svelte

// does not work
import { db } from "../firebase/firebase";

// does work, but file extension should not be used
import { db } from "../firebase/firebase.ts";

package.json

"sapper": "^0.28.0",
"svelte": "^3.17.3",
"svelte-preprocess": "^4.1.1",

[MALIK-0]

@kaisermann I'm still facing this issue and it's stopping me from using Typescript. If I add the .ts extension in the import everything compiles fine but I get no intellisense. If I remove the .ts extension I get intellisense but compiling stops working.

Can you point me in the right direction?

[kaisermann]

@TobiasMalikowski Is your bundler configured to automatically resolve ts extensions?

[MALIK-0]

@kaisermann Thanks for the quick reply. Yes it is, and in addition I could resolve it just in time :). The issue was caused by rollup-plugin-typescript2. I downgraded to version 0.21.0 and now the issue is resolved.

Just in case some else has this issue, this GitHub Issue pointed me in the right direction.