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Challenge 31: Array Diff

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/68af0687ef34c76c28ffa549.md

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--description--

Given two arrays with strings values, return a new array containing all the values that appear in only one of the arrays.

  • The returned array should be sorted in alphabetical order.

--hints--

arrayDiff(["apple", "banana"], ["apple", "banana", "cherry"]) should return ["cherry"].

js
assert.deepEqual(arrayDiff(["apple", "banana"], ["apple", "banana", "cherry"]), ["cherry"]);

arrayDiff(["apple", "banana", "cherry"], ["apple", "banana"]) should return ["cherry"].

js
assert.deepEqual(arrayDiff(["apple", "banana", "cherry"], ["apple", "banana"]), ["cherry"]);

arrayDiff(["one", "two", "three", "four", "six"], ["one", "three", "eight"]) should return ["eight", "four", "six", "two"].

js
assert.deepEqual(arrayDiff(["one", "two", "three", "four", "six"], ["one", "three", "eight"]), ["eight", "four", "six", "two"]);

arrayDiff(["two", "four", "five", "eight"], ["one", "two", "three", "four", "seven", "eight"]) should return ["five", "one", "seven", "three"].

js
assert.deepEqual(arrayDiff(["two", "four", "five", "eight"], ["one", "two", "three", "four", "seven", "eight"]), ["five", "one", "seven", "three"]);

arrayDiff(["I", "like", "freeCodeCamp"], ["I", "like", "rocks"]) should return ["freeCodeCamp", "rocks"].

js
assert.deepEqual(arrayDiff(["I", "like", "freeCodeCamp"], ["I", "like", "rocks"]), ["freeCodeCamp", "rocks"]);

--seed--

--seed-contents--

js
function arrayDiff(arr1, arr2) {

  return arr1;
}

--solutions--

js
function arrayDiff(arr1, arr2) {
  let unique1 = arr1.filter((v, i) => arr1.indexOf(v) === i);
  let unique2 = arr2.filter((v, i) => arr2.indexOf(v) === i);

  let only1 = unique1.filter(v => !unique2.includes(v));
  let only2 = unique2.filter(v => !unique1.includes(v));

  return [...only1, ...only2].sort();
}