WHATWG URL inconsistent 'origin' property

[mattyclarkson]

The whatwg-url npm package and URL class in Chrome/Safari perform the following with file:// URLs:

const url = new URL('file:///private/abc/music.aac');
console.log(url.origin);  // -> 'file://'

However, the built-in 'url' module and Firefox perform the following:

const url = new URL('file:///private/abc/music.aac');
console.log(url.origin);  // -> null

There is an inconsistency here. I had a look at the internal url.js and I'm not sure if the specification allows an opaque origin in this situation. I'd thought I report in case someone more familiar with the specification can determine if the inconsistency is allowed by the specification.

[addaleax]

/cc @nodejs/url

[TimothyGu]

This is unfortunately one of the unspecified areas in the URL Standard. See https://url.spec.whatwg.org/#concept-url-origin:

A URL’s origin is the origin returned by running these steps, switching on URL’s scheme:

"file"

Unfortunate as it is, this is left as an exercise to the reader. When in doubt, return a new opaque origin.

We followed the "when in doubt" instruction, but it did come as a surprise to me to find that whatwg-url doesn't.

[TimothyGu]

Firefox also returns null. Safari and Chrome both return "file://". Ugh.

[mattyclarkson]

Yup, seems like NodeJS is more inline with the specification. Is it worth moving upstream to Safari, Chrome, WHATWG URL to see what they think? I imagine there would be resistance to change as it might break backwards compatibility and, as it reads, they are compliant. I feel like the spec should really be tightened up there and just make everything return a null; you could return anything you like as a result of the exercise.

[mattyclarkson]

Have updated the OP with the new information about the inconsistencies.

[mattyclarkson]

Relevant issues:

• new URL('file://').origin is 'null' whatwg/url#310
• Empty or null host when scheme is "file:"? whatwg/url#258
• chromium#608606

[TimothyGu]

I don't think getting browsers to align with each other is within the scope of this project. I am pretty certain what we do is a fair behavior, and I'm going to file an issue at whatwg-url encouraging them to do the same as we do (pretty sure they'd agree), and then close this issue.

How's that sound?

[mattyclarkson]

Yup, totally on-board with that.