Truthfulness of empty arrays in Javascript… that’s not cool!

An empty array when cast to Boolean evaluates true, indicating that it is truthy.


An empty array compared to true evaluates false, indicating that it is not truthy.

[] == true
[] == false

And yet the Boolean opposite of an empty array still evaluates false, implying that the empty array is truthy.  What’s an interpreter to do?


Just some more contradictory anecdotal evidence to help drive you mad.

Boolean([]) == []
Boolean([]) == ![]
Boolean([]) == !![]
!Boolean([]) == []

Conclusion?  I’ll just bit my tongue this time.


About andyortlieb

I often find myself figuring out some niche oddities, only to find myself stuck on those same problems a year later due to my wide yet thin activity in certain topics related to my career and hobbies. This blog is where I document these nuances (or nuisances) to ease my pain the second time around, and hopefully that of some other fellow desperate internet scouts.
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