this post was submitted on 04 Jun 2025
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[–] [email protected] 8 points 3 days ago (2 children)
[–] [email protected] 6 points 3 days ago (1 children)

I'm guessing the + + in the middle returns NaN

[–] [email protected] 4 points 3 days ago

Indeed, the unary plus operator tries to convert whatever is after it to a number if it isn't already. Since 'a' is not a valid number, it returns NaN (not a number)

[–] [email protected] 2 points 3 days ago* (last edited 3 days ago) (2 children)

'a' + +

This part is the same as writing 'a'++ and that returns "NaN" (short for "not a number") since you can't increment a character, but this return type is a string, so the interpreter just concatenates it with the other letters: baNaNa. Then that string is converted to lower case to give the final result, "banana".

[–] [email protected] 6 points 3 days ago (1 children)

The space makes that two different tokens, in reality what happens is 'a' + (+'a') that resolves to 'a' + 'NaN'.

[–] [email protected] 2 points 2 days ago

Yep, I believe you're right

[–] [email protected] 3 points 3 days ago* (last edited 3 days ago)

Ironically 'a'++ works in C/C++ because 'a' is char where in JS 'a' is string.