Array.map does not work like map in other languages.<p>They decided that map shall receive the array index as the second argument, and there&#x27;s also a third argument that does something else. JS happily mashes these 3 arguments into parseInt&#x27;s argument list of (stringValue, radix) without error. Hilarity ensues.<p>(This code also sins against &quot;never call parseInt without the radix argument&quot;, see point about too many minefields to remember at once)