clever solution, thx

You are nice, man)

try 2 times)) its give the different test results)

Array.map(fn) executes a function on each item in an array and returns a new array of the transformed items.
more info on Array map here

x => doThing(x) is (practically) the same as function(x) { return doThing(x) }
more info on Arrow functions here

how it works? look at my solution its stupid((

I cant write right solution by JS

Works just fine, memoization at its best ;)

lol :D

omg

I did exactly