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JavaScript JavaScript Arrays Loop Through Arrays Locate and Join Array Elements

Posted by Ricardo Osorio
Ricardo Osorio
7,573 Points

Why 0 doesn't get the falsey if condition.

Hi,

according to the MDN link https://developer.mozilla.org/en-US/docs/Glossary/Falsy and what the videos says, 0(zero) should also be considered a falsey value (along with null and the others

Then why, if you paste the final code on the teacher's note and input 0 on the prompt dialog, you get the message "Sorry, we do not have 0." instead of the result of "in stock:</strong> ${inStock.join(', ')}"??

Thanks!!

1 Answer

Jennifer Nordell
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STAFF
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Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
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Jennifer Nordell
Treehouse Teacher

Hi there, Ricardo Osorio! You're correct that 0 is considered falsy. However, any input that is read in through the prompt is a string. Any non-empty string is considered truthy. So the Number 0 is different than the string "0" in terms of truthiness.

Way to dig into the documentation! Kudos. It took quite some time before I found the documentation understandable enough to make friends with it. It will be crucial going forward. Note that it says:

The Number zero (so, also 0.0, etc., and 0x0).

Hope this helps! :sparkles: