=== would disallow implicit conversion, so i'd imagine that wouldn't be any slower than == implicitly converting things.
Thinking about the performance of such an operator is surely premature optimization though.

wow, the fact that JS doesn't enforce how many args are passed to functions with an error is mildly horrifying to me.

any use of filter could generally be made better by passing a third parameter to filter and using that for comparison, which would compare to the new copy rather than comparing to the parameter of function.

Why is this rated so highly? This solution modifies input to then return a result, which is awful.

Use ordered dict to reduce time complexity