function forEach(collection, iteratee) {
      return (typeof iteratee == 'function' && isArray(collection))
        ? arrayEach(collection, iteratee)
        : baseEach(collection, getIteratee(iteratee));
    }
Iterates over elements of `collection` and invokes `iteratee` for each element.
The iteratee is invoked with three arguments: (value, index|key, collection).
Iteratee functions may exit iteration early by explicitly returning `false`.

**Note:** As with other "Collections" methods, objects with a "length"
property are iterated like arrays. To avoid this behavior use `_.forIn`
or `_.forOwn` for object iteration.

@static
@memberOf _
@since 0.1.0
@alias each
@category Collection
@param {Array|Object} collection The collection to iterate over.
@param {Function} [iteratee=_.identity] The function invoked per iteration.
@returns {Array|Object} Returns `collection`.
@example

_([1, 2]).forEach(function(value) {
  console.log(value);
});
// => Logs `1` then `2`.

_.forEach({ 'a': 1, 'b': 2 }, function(value, key) {
  console.log(key);
});
// => Logs 'a' then 'b' (iteration order is not guaranteed).