Bug repro for `vite-plugin-dts'

Bug: qmhc/vite-plugin-dts#280

The vite-plugin-dts v3.6.1 release added a Vue fix which sets the moduleResolution option to Node10 if it's not explicitly set in the tsconfig.json file. This overrides the default Typescript behavior of determining an implicit value based on the module option.

Due to this change, an implicitly typed export will not generate the correct type declaration file, which would should include an inlined import("<id>").<type> statement.

The bug still exists in v3.6.2.

Steps to reproduce

1. Clone this repo.
2. Run npm install at the repo root.
3. Run npm test at the repo root.

This will produce the error TS7006: Parameter 'response' implicitly has an 'any' type. error in the a package src/index.ts file at line 8.

If you check the emitted lib/index.d.ts type declaration file in the b package, you will see that type of the exported client instance is any.

export declare const client: any;

It should have a type which uses an inlined import(...) statement.

export declare const client: import("c").Client;

This repro is a monorepo, but the bug could also occur if the three packages were separate repos. The packages in this monorepo are as follows.

• a represents an "app" which is the end consumer of the b package. This is where the error becomes visible due to an unexpected any type in the build output of the b package, which leads to the TS7006 error.
• b represents an "internal" library which uses the client factory of the c package to export pre-configured client instances. In the original case, this was a DynamoDB Table client which implements business logic on top of the raw AWS SDK client. The exported client in this instance is a const with an implicit type which is implied by assigning the value returned by invoking the client factory. Everything looks correct in the source code of this library, and the library builds without error. However, the build output is not as expected.
• c represents an "external" library which provides a general purpose client factory. Nothing wrong here, but it's required to demonstrate the bug.

Workaround

Uncomment the moduleResolution option in the tsconfig.json file. And rerun the repro steps. No error occurs because the emitted type declaration in the b package is now correct.

Recommendation

I'm not sure why Vue requires the moduleResolution option to be explicitly set, but I think that the change should be reverted and the documentation updated to indicate that Vue users need to include the explicit option in their tsconfig.json file.

As it stands, everyone else will need to include the explicit option, and Vue users may get the result they need. Or, possibly the fix also causes unexpected loss of type information in Vue projects, which simply has been overlooked so far.