include returns incorrect result for undefined in IE #601

kopious opened this Issue May 10, 2012 · 1 comment


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kopious commented May 10, 2012

Reproduce the issue with the following in developer tools console:

Expected result: true

Result in IE 8: false


This is actually a rather infamous bug: IE <= 8 treats undefined array elements as elisions—it's as if you wrote _.include(Array(1), undefined), which is false in all browsers. Nothing much to be done, I'm afraid.

@jashkenas jashkenas closed this May 11, 2012
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