var baseEach = require('./_baseEach');

/**
 * Aggregates elements of `collection` on `accumulator` with keys transformed
 * by `iteratee` and values set by `setter`.
 *
 * @private
 * @param {Array|Object} collection The collection to iterate over.
 * @param {Function} setter The function to set `accumulator` values.
 * @param {Function} iteratee The iteratee to transform keys.
 * @param {Object} accumulator The initial aggregated object.
 * @returns {Function} Returns `accumulator`.
 */
function baseAggregator(collection, setter, iteratee, accumulator) {
  baseEach(collection, function(value, key, collection) {
    setter(accumulator, value, iteratee(value), collection);
  });
  return accumulator;
}

module.exports = baseAggregator;