function map(collection, iteratee, thisArg) {
  var func = isArray(collection) ? arrayMap : baseMap;
  iteratee = baseCallback(iteratee, thisArg, 3);
  return func(collection, iteratee);
}
Creates an array of values by running each element in `collection` through
`iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
arguments: (value, index|key, collection).

If a property name is provided for `iteratee` the created `_.property`
style callback returns the property value of the given element.

If a value is also provided for `thisArg` the created `_.matchesProperty`
style callback returns `true` for elements that have a matching property
value, else `false`.

If an object is provided for `iteratee` the created `_.matches` style
callback returns `true` for elements that have the properties of the given
object, else `false`.

Many lodash methods are guarded to work as iteratees for methods like
`_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.

The guarded methods are:
`ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
`drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
`parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
`trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
`sum`, `uniq`, and `words`

@static
@memberOf _
@alias collect
@category Collection
@param {Array|Object|string} collection The collection to iterate over.
@param {Function|Object|string} [iteratee=_.identity] The function invoked
 per iteration.
@param {*} [thisArg] The `this` binding of `iteratee`.
@returns {Array} Returns the new mapped array.
@example

function timesThree(n) {
  return n * 3;
}

_.map([1, 2], timesThree);
// => [3, 6]

_.map({ 'a': 1, 'b': 2 }, timesThree);
// => [3, 6] (iteration order is not guaranteed)

var users = [
  { 'user': 'barney' },
  { 'user': 'fred' }
];

// using the `_.property` callback shorthand
_.map(users, 'user');
// => ['barney', 'fred']