@arda well, we learn new things every day :) i never noticed that one button gets hidden once you use the other until you pointed it out - thanks! and sorry for the unnecessary suggestion
@arda hasOwnProperty is right there with typeof, 'in' and double negation, its complexity must be O(1) as well. So yes, it definitely wins over anything that spends time creating and iterating over arrays.
@arda not exactly, i just added an equivalent, simplified version to the existing test i linked earlier. There's a Fork button you can use to add you own test cases.
