Change:
The Bonfire says "Compare two arrays and return a new array with any items not found in both of the original arrays.". If you can't find an item in both arrays then the result will be infinite. The wording may be less confusing if it says: "Compare two arrays and return a new array with any items in the second array that are not found in the first."
Working on this!
"Compare two arrays and return a new array with any items in the second array that are not found in the first or any items in the first array that are not found in the second." i.e. "Return any items which doesn't exist in both the arrays."

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",