No documentation of '> ...' selector on .find()

[c-harding]

The function .find() supports selectors starting with a gt sign, >. This means that it will start the selector search with a direct child. This behaviour is, as far as I can see, undocumented.

[AurelioDeRosa]

You're right in saying that this is not documented. However, I don't think we should document or encourage it because that is a non-standard selector. In fact, it won't work with querySelector(). Any other opinion on this?

[mgol]

Leading combinators are perfectly fine and the upcoming .queryAll standard, once it finally materializes, will support them natively in browsers.

Using such selectors doesn't preclude the selector from going the querySelectorAll path as internally jQuery changes:

elem.find( "> .btn" );

to:

document.querySelectorAll( "#a-temporary-id-for-elem > .btn" );

I think this issue is valid and we should have it documented somewhere.

[AurelioDeRosa]

Cool. I wasn't aware queryAll() was going to support such selectors.

[mgol]

querySelectorAll wasn't able to support them because it runs queries against the whole document and only afterwards filters out everything not contained within the queried context. This is contrary to how jQuery (& most other libraries at the time) selection worked (.queryAll is planned specifically to fix these issues) and made selectors with leading combinators impossible - a problem John Resig complained about in 2008. :)

[kswedberg]

@mgol : it looks like .queryAll() has been removed from the DOM spec…
http://stackoverflow.com/questions/23269785/whats-the-difference-between-queryall-and-queryselectorall#38245620

[mgol]

@kswedberg They have been removed until some details in how it should utilize JS subclassing etc. are resolved. They should be back once all the details are fleshed out (I hope!).

In any case, such selectors in jQuery are perfectly fine and use the fast qSA path so this issue is still valid. :)

[kswedberg]

@mgol : yes, I agree about the main issue, of course: these selectors are perfectly fine in jQuery. 👍