Underscore.js 1.7の使い方 Collections編 map

var r = document.getElementById("r");
  _.map([1, 2, 3], function(num) {
  r.innerHTML += num * 2 + '
';
});
// => 2

// => 4

// => 6

var r2 = document.getElementById("r2");
  _.map({one: 1, two: 2, three: 3}, function(num, key) {
  r2.innerHTML += num * 2 + '
';
});
// => 2

// => 4

// => 6