Does not allow length checks on jQuery objects #21

lazd opened this Issue Oct 16, 2012 · 13 comments


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lazd commented Oct 16, 2012

We may need to test that an exact number of elements match a selector, and it seems chai-jquery breaks previously methods of doing this. Previously, we were doing:

expect(el.find('.modal-footer button')).to.have.length(2);

But this fails when chai-jquery is included:

'1' is not a function (evaluating 'expect(el.find('.modal-footer button')).to.have.length(2)')

In order to get our tests to run, we had to change it to:

expect(el.find('.modal-footer button').length).to.equal(2);

Is there a better recommended way of accomplishing this using chai-jquery? have is not sufficient as it only tests if at least one descendant is present.


jfirebaugh commented Oct 17, 2012

I don't think this is fixable without removing support for expect($(...)).to.have(selector). That requires that the have property return a function, and a function's length property is not writable.

What I could do is support this:

expect(el).to.have(2, '.modal-footer button');

Would that be satisfactory?


jfirebaugh commented Oct 17, 2012

BTW, you can also do:

expect(el.find('.modal-footer button')).to.have.lengthOf(2);

RStankov commented Nov 7, 2012

My pull request #22 will give the option todo:

expect(el.find('.modal-footer button')).to.have.size(2);

domenic commented Dec 13, 2012

This should be fixable using Chai's addChainableMethod...


jfirebaugh commented Dec 14, 2012

@domenic Can you elaborate? My analysis was that if have is a function, there's no way for have.length(n) to also work, since a function's length property is not writable.


domenic commented Dec 15, 2012

@jfirebaugh ah right :(. didn't read very well...


domenic commented Dec 16, 2012


expect(el.find('.modal-footer button'));

jfirebaugh commented Dec 27, 2012

Nice, I'm going to note this issue in the README and suggest that as the official workaround.

jfirebaugh closed this Dec 27, 2012

asmblah commented Mar 13, 2013

This is a shame, this is a blocking issue that has stopped me from using this in a project already using Chai and a lot of existing expect(...).to.have.length(...); :(

I would suggest replacing the expect(...).to.have(...); syntax with expect(...).to.have.descendant(...); or expect(...).to.have.descendant.matching(...); or something similar if it was earlier in the process to avoid breaking existing Chai behaviour.

lazd commented Mar 13, 2013

@asmblah: Is it that neither of the workarounds meet your use case, or that you would prefer a more expressive statement?

Although they're not gorgeous, either of these workarounds should unblock you:

expect(el.find('.modal-footer button').length).to.equal(2);


expect(el.find('.modal-footer button'));

asmblah commented Mar 14, 2013

Hi @lazd,

Thanks for the response. No, the issue is that the test codebase already uses expect(<array>).to.have.length(7); etc. in many places which are then broken when including the chai-jquery library. I understand that alternative syntaxes exist but do not want to change all those references.

What I meant was, if the expect(...).to.have.* syntax hadn't been broken by chai-jquery, instead being implemented as expect(...).to.have.descendant(...); or similar, then I could have made use of the library.

Would a pull request with changes to support a config option switching on/off the overriding of have with a function and instead supporting an expect(...).to.have.descendant(...); (or similar) be acceptable?

akalman commented Oct 14, 2014

Since chai-jquery doesn't seem to use have as a function anymore, is this fixable now?


jfirebaugh commented Oct 14, 2014

Removing the overload of have was the fix; expect(el.find('.modal-footer button')).to.have.length(2) should work in 2.0.

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