HORIZON PROJECT

var baseFlatten = require('./_baseFlatten'),

    map = require('./map');

/**

 * Creates a flattened array of values by running each element in `collection`

 * thru `iteratee` and flattening the mapped results. The iteratee is invoked

 * with three arguments: (value, index|key, collection).

 *

 * @static

 * @memberOf _

 * @since 4.0.0

 * @category Collection

 * @param {Array|Object} collection The collection to iterate over.

 * @param {Function} [iteratee=_.identity] The function invoked per iteration.

 * @returns {Array} Returns the new flattened array.

 * @example

 *

 * function duplicate(n) {

 *   return [n, n];

 * }

 *

 * _.flatMap([1, 2], duplicate);

 * // => [1, 1, 2, 2]

 */

function flatMap(collection, iteratee) {

  return baseFlatten(map(collection, iteratee), 1);

}

module.exports = flatMap;