HORIZON PROJECT

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

    map = require('./map');

/** Used as references for various `Number` constants. */

var INFINITY = 1 / 0;

/**

 * This method is like `_.flatMap` except that it recursively flattens the

 * mapped results.

 *

 * @static

 * @memberOf _

 * @since 4.7.0

 * @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]]];

 * }

 *

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

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

 */

function flatMapDeep(collection, iteratee) {

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

}

module.exports = flatMapDeep;