Function map

test/cases/simple_generic.js:6–10

(arr, f)

last(["a", "b", "c"]); //: string

function map(arr, f) {
  var res = [];
  for (var i = 0; i < arr.length; ++i) res.push(f(arr[i]));
  return res;
}

map([1, 2, 3], function() { return "X"; }); //: [string]
map([1, 2, 3], function() { return true; }); //: [bool]