// Curring Adding two items const sum = x => y => x + y sum(2)(2)//4 // Adding three or more items const sum = x => (y=0) => (...z) => +x + +y + +z.reduce((prev,curr)=>prev+curr,0) sum(2)()()//2 sum(2)(2)()//4 sum(2)(2)(2)//6 sum(2)(2)(2)(2)//8