Merge pull request #1275 from jun-low/new/is-duplicate

Add isDuplicates

snippets/isDuplicates.md

@@ -0,0 +1,18 @@
+---
+title: hasDuplicates
+tags: array,beginner
+---
+
+Checks if there are duplicate values in a flat array.
+
+- Use `Set()` to get the unique values in the array.
+- Use `Set.prototype.size` and `Array.prototype.length` to check if the count of the unique values is the same as elements in the original array.
+
+```js
+const hasDuplicates = arr => new Set(arr).size !== arr.length;
+```
+
+```js
+hasDuplicates([0,1,1,2]); // true
+hasDuplicates([0,1,2,3,]); // false
+```