/**
 * lodash 4.2.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */
var baseFlatten = require('lodash._baseflatten');

/**
 * Creates a new array concatenating `array` with `other`.
 *
 * @private
 * @param {Array} array The first array to concatenate.
 * @param {Array} other The second array to concatenate.
 * @returns {Array} Returns the new concatenated array.
 */
function arrayConcat(array, other) {
  var index = -1,
      length = array.length,
      othIndex = -1,
      othLength = other.length,
      result = Array(length + othLength);

  while (++index < length) {
    result[index] = array[index];
  }
  while (++othIndex < othLength) {
    result[index++] = other[othIndex];
  }
  return result;
}

/**
 * Copies the values of `source` to `array`.
 *
 * @private
 * @param {Array} source The array to copy values from.
 * @param {Array} [array=[]] The array to copy values to.
 * @returns {Array} Returns `array`.
 */
function copyArray(source, array) {
  var index = -1,
      length = source.length;

  array || (array = Array(length));
  while (++index < length) {
    array[index] = source[index];
  }
  return array;
}

/**
 * Creates a new array concatenating `array` with any additional arrays
 * and/or values.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Array
 * @param {Array} array The array to concatenate.
 * @param {...*} [values] The values to concatenate.
 * @returns {Array} Returns the new concatenated array.
 * @example
 *
 * var array = [1];
 * var other = _.concat(array, 2, [3], [[4]]);
 *
 * console.log(other);
 * // => [1, 2, 3, [4]]
 *
 * console.log(array);
 * // => [1]
 */
function concat() {
  var length = arguments.length,
      array = castArray(arguments[0]);

  if (length < 2) {
    return length ? copyArray(array) : [];
  }
  var args = Array(length - 1);
  while (length--) {
    args[length - 1] = arguments[length];
  }
  return arrayConcat(array, baseFlatten(args, 1));
}

/**
 * Casts `value` as an array if it's not one.
 *
 * @static
 * @memberOf _
 * @since 4.4.0
 * @category Lang
 * @param {*} value The value to inspect.
 * @returns {Array} Returns the cast array.
 * @example
 *
 * _.castArray(1);
 * // => [1]
 *
 * _.castArray({ 'a': 1 });
 * // => [{ 'a': 1 }]
 *
 * _.castArray('abc');
 * // => ['abc']
 *
 * _.castArray(null);
 * // => [null]
 *
 * _.castArray(undefined);
 * // => [undefined]
 *
 * _.castArray();
 * // => []
 *
 * var array = [1, 2, 3];
 * console.log(_.castArray(array) === array);
 * // => true
 */
function castArray() {
  if (!arguments.length) {
    return [];
  }
  var value = arguments[0];
  return isArray(value) ? value : [value];
}

/**
 * Checks if `value` is classified as an `Array` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @type {Function}
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified,
 *  else `false`.
 * @example
 *
 * _.isArray([1, 2, 3]);
 * // => true
 *
 * _.isArray(document.body.children);
 * // => false
 *
 * _.isArray('abc');
 * // => false
 *
 * _.isArray(_.noop);
 * // => false
 */
var isArray = Array.isArray;

module.exports = concat;