Change:
Challenge has an issue. User Agent is: <codeMozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2547.0 Safari/537.36</code. My following code successfully satisfies the criteria and all the tests, except one due to an inconsistency. ! The returned array will be sorted due to my method. The last test has no issue with my output being in sorted order, yet expects the output to retain the same order, as my output is not accepted. This is inconsistent, and it should also accept the answer regardless of its order. To bypass this I would have to implement a check to see if one of the given arrays is empty and if so, return the other as is, which is not part of the exercise's criteria.
Thanks guys!

Discussion:
"id": "a5de63ebea8dbee56860f4f2", "title": "Diff Two Arrays", "description": [ <del> "Compare two arrays and return a new array with any items not found in both of the original arrays.", </del> <ins> "Compare two arrays and return a new array with any items only found in one of the original arrays.", </ins> "Remember to use <a href='//github.com/FreeCodeCamp/freecodecamp/wiki/How-to-get-help-when-you-get-stuck' target='_blank'>Read-Search-Ask</a> if you get stuck. Try to pair program. Write your own code." ], "challengeSeed": [

], "tests": [ "assert(typeof(diff([1, 2, 3, 5], [1, 2, 3, 4, 5])) === "object", 'message: <code>diff()</code> should return an array.');", <del> "assert.deepEqual(diff(["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]), ["pink wool"], 'message: <code>["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]</code> should return <code>["pink wool"]</code>.');", "assert.includeMembers(diff(["andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]), ["diorite", "pink wool"], 'message: <code>["andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]</code> should return <code>["diorite", "pink wool"]</code>.');", "assert.deepEqual(diff(["andesite", "grass", "dirt", "dead shrub"], ["andesite", "grass", "dirt", "dead shrub"]), [], 'message: <code>["andesite", "grass", "dirt", "dead shrub"], ["andesite", "grass", "dirt", "dead shrub"]</code> should return <code>[]</code>.');", "assert.deepEqual(diff([1, 2, 3, 5], [1, 2, 3, 4, 5]), [4], 'message: <code>[1, 2, 3, 5], [1, 2, 3, 4, 5]</code> should return <code>[4]</code>.');", "assert.includeMembers(diff([1, "calf", 3, "piglet"], [1, "calf", 3, 4]), ["piglet", 4], 'message: <code>[1, "calf", 3, "piglet"], [1, "calf", 3, 4]</code> should return <code>["piglet", 4]</code>.');", "assert.deepEqual(diff([], ["snuffleupagus", "cookie monster", "elmo"]), ["snuffleupagus", "cookie monster", "elmo"], 'message: <code>[], ["snuffleupagus", "cookie monster", "elmo"]</code> should return <code>["snuffleupagus", "cookie monster", "elmo"]</code>.');", "assert.includeMembers(diff([1, "calf", 3, "piglet"], [7, "filly"]), [1, "calf", 3, "piglet", 7, "filly"], 'message: <code>[1, "calf", 3, "piglet"], [7, "filly"]</code> should return <code>[1, "calf", 3, "piglet", 7, "filly"]</code>.');" </del> <ins> "assert.sameMembers(diff(["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]), ["pink wool"], 'message: <code>["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]</code> should return <code>["pink wool"]</code>.');", "assert.sameMembers(diff(["andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]), ["diorite", "pink wool"], 'message: <code>["andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]</code> should return <code>["diorite", "pink wool"]</code>.');", "assert.sameMembers(diff(["andesite", "grass", "dirt", "dead shrub"], ["andesite", "grass", "dirt", "dead shrub"]), [], 'message: <code>["andesite", "grass", "dirt", "dead shrub"], ["andesite", "grass", "dirt", "dead shrub"]</code> should return <code>[]</code>.');", "assert.sameMembers(diff([1, 2, 3, 5], [1, 2, 3, 4, 5]), [4], 'message: <code>[1, 2, 3, 5], [1, 2, 3, 4, 5]</code> should return <code>[4]</code>.');", "assert.sameMembers(diff([1, "calf", 3, "piglet"], [1, "calf", 3, 4]), ["piglet", 4], 'message: <code>[1, "calf", 3, "piglet"], [1, "calf", 3, 4]</code> should return <code>["piglet", 4]</code>.');", "assert.sameMembers(diff([], ["snuffleupagus", "cookie monster", "elmo"]), ["snuffleupagus", "cookie monster", "elmo"], 'message: <code>[], ["snuffleupagus", "cookie monster", "elmo"]</code> should return <code>["snuffleupagus", "cookie monster", "elmo"]</code>.');", "assert.sameMembers(diff([1, "calf", 3, "piglet"], [7, "filly"]), [1, "calf", 3, "piglet", 7, "filly"], 'message: <code>[1, "calf", 3, "piglet"], [7, "filly"]</code> should return <code>[1, "calf", 3, "piglet", 7, "filly"]</code>.');" </ins> ], "MDNlinks": [ "Comparison Operators",