Document File name has a '.js' extension - stripping it

TypeScript Version: 4.2.0-dev.20201211

Search Terms: typescript File name has a '.js' extension - stripping it

Code

https://github.com/sguillia/ts-repro-III

other.ts

import * as index from "./index.js"

index.ts

export { }

Compile with:

tsc other.ts --traceResolution

Expected behavior:

Does not compile?

Actual behavior:

$ tsc other.ts --traceResolution
...
File name '/path/to/ts-repro-III/index.js' has a '.js' extension - stripping it.
...

This document is very good:
https://www.typescriptlang.org/docs/handbook/module-resolution.html

But it doesn't talk about resolution of modules with their extensions.

The actual behavior is fine but I did not manage to find its documentation

Same issue for jsx

$ tsc other.ts --traceResolution
...
File name '/path/to/ts-repro-III/index.jsx' has a '.jsx' extension - stripping it.
...

Would it be possible to document

• which extension are trimmed?
• what look-ups are performed based on the file name with extension stripped?

Playground Link: https://github.com/sguillia/ts-repro-III

Related Issues: no

Issue にリンクされているモジュール解決の handbook ページから始め、現在の説明を .js と .jsx の例に対する traceResolution の出力と比較してください。どの拡張子が取り除かれ、どの lookup が続いて行われるのかを記録し、そのページがコンパイラーの動作を変更せずに両方の質問へ回答していることを確認してください。