composition and map

compmap.js

// composition = f(g(x))
var compose = function(f, g) {
  return function(x) {
    return f(g(x));
  }
}

var squareAdd10 = compose(square, add10);
[1, 2, 3, 4, 5].map(squareAdd10); // 11, 14, 19, 26, 35
// or
var squared = [1, 2, 3, 4, 5].map(square); // 1, 4, 9, 16, 25
var added = [1, 2, 3, 4, 5].map(add10); // 11, 14, 19, 26, 35