Import are case insensitive in window 10

[GrosSacASac]

• Version:15.2.1
• Platform:window 10
• Subsystem:IMPORT

What steps will reproduce the bug?

a.js

import {b} from "./B.js";

b.js

export {b};
const b = 10;

package.json

{
  "version": "1.0.0",
  "type": "module",
  "private": true
}

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior?

B.js not found (Uppercase)

What do you see instead?

no errors

Additional information

It creates error on linux

[devsnek]

this is because the filesystem on your windows machine is case insensitive. not much we can do about that.

[aduh95]

There are quite a lot of layers between Node.js ESM loader and the actual file on your hardware. The gist of it is that it relies on the Windows API, which is case insensitive by default. If you check the Windows API documentation, you can see there is a FILE_FLAG_POSIX_SEMANTICS flag that does enable case sensitivity in Windows. As the documentation indicates, this option could break other applications written and I guess that's why libuv doesn't use it.

I suggest to open an issue on libuv/libuv (the library Node.js relies on for FS related operations) asking for this flag to be enabled. They'll know if that's something possible without breaking the ecosystem.

[GrosSacASac]

May I suggest, do not use libuv fs for imports and instead implement something more strict.

I feel like this will create a lot of "but in works on my machine !" - type of situation especially in team where some developers have Linux and some have windows machines. And it is not only for backend since a lot of Front End tools use NodeJs as well nowadays.

[aduh95]

do not use libuv fs for imports and instead implement something more strict

Well, you are very welcome to open a PR, but I doubt it's a reasonable way of solving your issue. Also, there are filesystems out there which are case insensitive (E.G.: HFS+), and there is no way around that on the software level.

[j1mmie]

Sorry for the necro and somewhat off-topic comment. But for Typescript users who come here via Google, there's a config option to detect similar imports that have mismatched casing:

forceConsistentCasingInFileNames in TSConfig

Not perfect, but still helpful. There's a long-running issue over at the Typescript repo that seems to be making some progress though: microsoft/TypeScript#21736

[RedYetiDev]

Well, you are very welcome to open a PR, but I doubt it's a reasonable way of solving your issue. Also, there are filesystems out there which are case insensitive (E.G.: HFS+), and there is no way around that on the software level.

It seems this is working as intended, so I'm closing this issue, but if anyone disagrees, please re-open