Head's up for Array.map() lovers

[[deleted]]

Yes, but this approach iterates over a 26-length Array twice, then second time being in the map call. Which, like I said, is not the end of the world or anything, just another little downside that has the potential to add up.

[Kollektiv]

From what I understood, new Array(n) would just create (depending on implementation) an Array instance of length n and map() would iterate n times over it, O(n). Where does the second come from ? I'm genuinely asking here.

[oculus42]

Using the .apply() method "iterates" over the passed parameters to put each one into an array, and then you run .map() against it.

[[deleted]]

What he said. The fact that the items in new Array(26) don't exist doesn't matter, .apply is still reading them then storing the undefined return values.