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javascript/snippets/unique-symmetric-difference.md

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+---
+title: Array unique symmetric difference
+type: snippet
+tags: [array,math]
+cover: paper-card
+dateModified: 2020-10-22T20:24:44+03:00
+---
+
+Returns the unique symmetric difference between two arrays, not containing duplicate values from either array.
+
+- Use `Array.prototype.filter()` and `Array.prototype.includes()` on each array to remove values contained in the other.
+- Create a `Set` from the results, removing duplicate values.
+
+```js
+const uniqueSymmetricDifference = (a, b) => [
+  ...new Set([
+    ...a.filter(v => !b.includes(v)),
+    ...b.filter(v => !a.includes(v)),
+  ]),
+];
+```
+
+```js
+uniqueSymmetricDifference([1, 2, 3], [1, 2, 4]); // [3, 4]
+uniqueSymmetricDifference([1, 2, 2], [1, 3, 1]); // [2, 3]
+```