function baseMap(collection, iteratee) {
      var result = [];

      baseEach(collection, function(value, key, collection) {
        result.push(iteratee(value, key, collection));
      });
      return result;
    }
The base implementation of `_.map` without support for callback shorthands
or `this` binding.

@private
@param {Array|Object|string} collection The collection to iterate over.
@param {Function} iteratee The function invoked per iteration.
@returns {Array} Returns the new mapped array.