In today's edition of "oh my god everything is so freaking interconnected", I learned a W I L D thing about JavaScript's parseInt function:
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So what happens when you try to parseInt() something that's not a number? It ought to return NaN, as it's not a number. Except LOOK at this:pic.twitter.com/tTP0qeTvvD
That "parseInt('null', 24)" returns 23 is quite sensible. But that "parseInt(null, 24)" returns 23 is a crime against humanity.pic.twitter.com/eSGrEgGg9K
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The part of the former that's not entirely sensible is that it seems to lack any way to say the entire input wasn't consumed/valid.
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As opposed to strtol which exposes this part of the outcome via *endptr.
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I guess that parseInt is defined first doing arg0.toString()?
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Almost. It calls ToString(arg0). (Sect. 15.1.2.2 of 3rd edition of ECMA-262 from 1999, I don't know if this changed in newer editions.)pic.twitter.com/ugcoU1zMzk
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Upon some thinking, I saw why it behaves that way: Consider 012...89abc...lmn. Counting from 0, 'n' is 23rd #. So it parsed 'null', and >>
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it stopped at 'u' since that is outside the range (base 24), so it converted 'n' into number 23. There! But it does confuse us humans!
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