Merge pull request #1639 from komputarist/master

Added allUnique snippet
Resolves #1638

snippets/allUnique.md

@@ -0,0 +1,18 @@
+---
+title: allUnique
+tags: array,beginner
+---
+
+Checks if all elements in an array are unique.
+
+- Create a new `Set` from the mapped values to keep only unique occurences.
+- Use `Array.prototype.length` and `Set.prototype.size` to compare the length of the unique values to the original array.
+
+```js
+const allUnique = arr => arr.length === new Set(arr).size;
+```
+
+```js
+allUnique([1, 2, 3, 4]); // true
+allUnique([1, 1, 2, 3]); // false
+```