> This isn't strange or surprising. > You just have to know this Hidden, silent, unintuitive behavior that you "just have to know" (and remember each time you

> This isn't strange or surprising. > You just have to know this Hidden, silent, unintuitive behavior that you "just have to know" (and remember each time you might read or write the code) is absolutely strange and surprising in an engineering context. Javascript's deadly combination of unnecessary unintuitiveness (map's ludicrous API) and permissibility (ignoring extra arguments) strikes again. The permissibility of guessing what malformed code means is actually somewhat defensible in Javascript's case, since the incentive ecosystem of the Web is complex and frontend parsing has long had a tradition of best-effort parsing instead of throwing an exception. But the absurd signature of map here is half the problem, and there's really no good explanation for that than yet another instance of "Javascript is a dumpster fire that should only be used when forced to". Similarly "easy-to-use" languages like Python can afford strong typing and rejecting extra args when not specified because they're not bound by the Web's permissibility. But Python also, for all its flaws, has adults making language decisions and does the sane thing with APIs like map without loss of expressiveness. Adding loop metadata like indices requires an explicit call to enumerate(), trading off an iota of verbosity for intuitiveness, which is one of the most important things in writing code that can remain productive and bug-free.