Your map callback is more complicated that it needs to be. You dont need an if statement or curly braces.
You can take a loot at this, specifically the second example and then figure out how to write that as an arrow function in the .map() to work for your problem. https://www.w3schools.com/jsref/jsref_map.asp
I did not realize they were only supposed to do positive integers. I could have provided some better information otherwise. Going to start asking for links to the challenges so i can better understand what is needing to be accomplished.
Thefilter() is used when you want to output only the conditions you specify within the () which is usually a function.
the reduce()method will reduce the elements of your array to only one output . What the reduce() method should do with the elements of your array ,you write that code within the () which is is also a function.
the map() method is used on an array when you want to do something with each element of an array and output an array.