How to prevent automatic sort of Object numeric property?

Question

Why I met this problem: I tried to solve an algorithm problem and I need to return the number which appeared most of the times in an array. Like [5,4,3,2,1,1] should return

Answer 1

You are using a JS object, that by definition does not keep order. Think of it as a key => value map.

You should be using an array, that will keep whatever you insert on the index you inserted it into. Think of it as a list.

Also notice that you did not in fact "reverse the order of the assignment", because you inserted elements on the same index every time.