array.map(param1[, param2]);
// param1 - Function(value, index, array)
// param2 - Object (to bind as this)

// EXAMPLE
[1, 2, 3, 4, 5].map((val, i, arr) => {
  if (arr[i] === val) // always true
    return val + i;
}); // [1, 3, 5, 7, 9]