$(undefined).prop('href') throws error

[rla]

$(undefined).prop('href') throws:

TypeError: Cannot read property 'hasOwnProperty' of undefined.

With jQuery the same expression returns undefined.

Tested with Cheerio 0.20.0

[sotojuan]

Seems like the problem is here?

[rla]

@sotojuan, if you are interested in taking over then go ahead.

[elias-winberg]

It should be relatively easy to fix, no? If el isn't a valid tag immediately return. I'll try to create a pull request.

[Delgan]

Is it related to #554?

[elias-winberg]

Sort of, jQuery creates the element even if the attribute value is undefined, and cheerio doesn't.

[rla]

I add some background info.

The bug might also be triggered when the selector does not match, like in the code:

$('.not-exists').attr('href')

It was not enough to check that $('.not-exists') is truthy before calling .attr() method. $ is Cheerio here. I ported the code from code using querySelector that behaves way more logically than jQuery.

Looking through the current Cheerio tests, it does not seem to consider negative cases when some input is undefiend or null.

[elias-winberg]

.attr seems to be working as expected though (only .prop throws an error if the selector is invalid). I think this is due to the fact that the .getProp function lacks this line.

[fb55]

Fixed in #880