freeCodeCamp/guide/english/certifications/coding-interview-prep/rosetta-code/symmetric-difference/index.md

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title: Symmetric difference
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# Symmetric difference

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## Solutions

<details><summary>Solution 1 (Click to Show/Hide)</summary>

```javascript
function symmetricDifference(A, B) {
  function relative_complement(A, B) {
    return A.filter(function(elem) {
      return B.indexOf(elem) == -1
    });
  }

  function unique(ary) {
    var u = ary.concat().sort();
    for (var i = 1; i < u.length;) {
      if (u[i - 1] === u[i])
        u.splice(i, 1);
      else
        i++;
    }
    return u;
  }

  return unique(relative_complement(A, B).concat(relative_complement(B, A))).sort();
}
```

</details>