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JavaScript: why does parseInt(1/0, 19) return 18?
Why does parseInt(1/0, 19) evaluate to 18 in Javascript ? I understand 19 in not a permissible radix but still can someone tell how things are working here ?
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4Why are you dividing by zero? – antyrat Jul 06 '12 at 15:17
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+1, this is fascinating: `parseInt(1/0, 15) --> NaN parseInt(1/0, 19) --> 18 parseInt(1/0, 20) --> 18 parseInt(1/0, 25) --> 185011843 parseInt(1/0, 28) --> 324267766` – Claudiu Jul 06 '12 at 15:18
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Let's say I am passing an expression to parseInt taken from user & he may type whatever he feels like. It hurts to cover corner cases but still someone has to. – anuj_io Jul 06 '12 at 15:19
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19 *is* a permissible radix... a more pertinent question is, why are you converting to base-19? – Dancrumb Jul 06 '12 at 15:19
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Thanks for pointing to the right place. :) – anuj_io Jul 06 '12 at 15:20
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Also, this is an exact duplicate – Dancrumb Jul 06 '12 at 15:20
1 Answers
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Ah, quick javascript consoling led to the answer:
> 1/0
Infinity
> parseInt("Infinity", 19)
18
parseInt seems to convert the first argument to a string, e.g.:
> parseInt(11, 2)
3
so, it's converting the string "Infinity", which explains everything.
Claudiu
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