fileURLToPath returns forward slashes on Windows

[zenparsing]

• Version: v11.6.0
• Platform: Win64
• Subsystem: url

url.fileURLToPath results in a path containing forward slashes instead of backslashes on Windows.

url.fileURLToPath('file:///C:/Users/zenparsing/Code');
// 'C:/Users/zenparsing/Code'

[devsnek]

cc @nodejs/url

[seishun]

As far as I can tell, this function has never worked as documented, even in the commit that added it (eef072f):

> url.fileURLToPath('file:///C:/path/')
'C:/path/'

cc @guybedford

[zenparsing]

It doesn't look like there are any tests for this function. I can put together a PR over the next couple of days, if that seems like a good direction.

[guybedford]

@zenparsing thanks for reporting, that would be really great.

[guybedford]

I guess the main thing is that there is the concept of whether / can be standardized as the method of windows paths support. See eg denoland/deno#957.

Personally I do prefer this style in cross-env app development, only doing \\ replacement when needed in arg parsing, but whether Node should have it by default is debatable.

[jdalton]

It looks like this API was added without tests and this looks like a valid bug.
The docs for it show the expected result:

new URL('file:///C:/path/').pathname;    // Incorrect: /C:/path/
fileURLToPath('file:///C:/path/');       // Correct:   C:\path\ (Windows)

new URL('file://nas/foo.txt').pathname;  // Incorrect: /foo.txt
fileURLToPath('file://nas/foo.txt');     // Correct:   \\nas\foo.txt (Windows)

Currently the actual results on Windows are

url.fileURLToPath('file:///C:/path/') // Incorrect: 'C:/path/'
url.fileURLToPath('file://nas/foo.txt') // Incorrect: '//nas/foo.txt'

Other file path APIs (path.normalize, etc.) appear to return paths with backslashes on Windows.
Marking as a bug since it looks to meet the bar.