var baseFlatten = require('../internal/baseFlatten'),
      baseUniq = require('../internal/baseUniq'),
      restParam = require('../function/restParam');
  
  /**
   * Creates an array of unique values, in order, from all of the provided arrays
   * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
   * for equality comparisons.
   *
   * @static
   * @memberOf _
   * @category Array
   * @param {...Array} [arrays] The arrays to inspect.
   * @returns {Array} Returns the new array of combined values.
   * @example
   *
   * _.union([1, 2], [4, 2], [2, 1]);
   * // => [1, 2, 4]
   */
  var union = restParam(function(arrays) {
    return baseUniq(baseFlatten(arrays, false, true));
  });
  
  module.exports = union;