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var baseFlatten = require('./_baseFlatten'),    baseIteratee = require('./_baseIteratee'),    baseRest = require('./_baseRest'),    baseUniq = require('./_baseUniq'),    isArrayLikeObject = require('./isArrayLikeObject'),    last = require('./last');
/** * This method is like `_.union` except that it accepts `iteratee` which is * invoked for each element of each `arrays` to generate the criterion by * which uniqueness is computed. Result values are chosen from the first * array in which the value occurs. The iteratee is invoked with one argument: * (value). * * @static * @memberOf _ * @since 4.0.0 * @category Array * @param {...Array} [arrays] The arrays to inspect. * @param {Function} [iteratee=_.identity] The iteratee invoked per element. * @returns {Array} Returns the new array of combined values. * @example * * _.unionBy([2.1], [1.2, 2.3], Math.floor); * // => [2.1, 1.2] * * // The `_.property` iteratee shorthand. * _.unionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x'); * // => [{ 'x': 1 }, { 'x': 2 }] */var unionBy = baseRest(function(arrays) {  var iteratee = last(arrays);  if (isArrayLikeObject(iteratee)) {    iteratee = undefined;  }  return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), baseIteratee(iteratee, 2));});
module.exports = unionBy;