import from "." doesn't reference folder if folder and file have same name

[ghost]

Bug Report

🔎 Search Terms

import folder file refactor

🕗 Version & Regression Information

4.4.0-insiders.20210805, next, and the 4.3.x branch

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about ...?

⏯ Playground Link

Can't reproduce in playground as it has to do with multiple files and imports

💻 Code

This has to do with file imports, so I made a minimal repro:

https://github.com/MarkKahn/ts-import-refactor-bug.git

🙁 Actual behavior

I was refactoring a file, module.ts into a directory, module. I created module/index.ts, and in module/submodule.ts I had written: import { otherSubModule } from '.'

TS threw an error saying Module '"."' has no exported member 'otherSubModule'.ts(2305)

After some banging my head on the wall I figured out that from '.' wasn't referencing ./index.ts, but instead was referencing ../module.ts

🙂 Expected behavior

import from '.' should reference the current folder, always. This is likely only a bug that would be triggered when refactoring code as I can't think of a use case for a file and folder to have the same name and be a valid structure.

[andrewbranch]

Your minimal repro doesn’t seem to be a repro—it doesn’t have any imports from "."

[ghost]

whoops, I hit undo one too many times before committing. Fixed, sorry. Issue is in a/c.ts

[andrewbranch]

Thanks! Now if you don’t mind, can you restate your actual behavior and expected behavior in terms of the file names and identifiers used in that repro? I had a little trouble following your hypothetical example.

[ghost]

Sure.

c.ts

import { b } from '.';

I would expect '.' here to look at index.ts in the same folder. It doesn't, it references ../a.ts instead.

[ghost]

Also I just tested this in node using module.exports and require, and require('.') does reference the folder.

And I learned that es6 modules oddly don't officially support directory imports...

[Jamesernator]

So in Node's official ESM support yes you can't import directories, you have to import the file you want directly or use a package and "exports".

Technically TypeScript doesn't support Node's ESM behaviour at all atm. Although the issue you're getting is a TypeScript specific issue as it only recognizes CommonJS style imports atm. So yeah import foo from '.'; should resolve the same as import foo = require('.'); in TypeScript's current resolution.

Proper ESM support with the same behaviour as Node's esm mode is expected in the next major version of TypeScript (but it could be delayed as its a big job). In this case it should be an error as per Node's official ESM resolution.