[Solved] Javascript function with some input and output [closed]

If you mean

function foo(x){ 
  return function(y){
    return x+y;
  }
}

Then foo(5) returns a function that takes another parameter, (y).
So foo(5)(6) inputs 5 to foo, and 6 to bar.

foo(5)(6) returns 11

foo(4) returns a function(y){ return 4 + y;}

foo(7) returns a function(y){ return 7 + y;}