Rename js snippets

snippets/js/s/most-frequent-array-element.md

@@ -0,0 +1,28 @@
+---
+title: Most frequent element in array
+type: snippet
+language: javascript
+tags: [array]
+author: chalarangelo
+cover: clock
+dateModified: 2020-09-15T16:28:04+03:00
+---
+
+Returns the most frequent element in an array.
+
+- Use `Array.prototype.reduce()` to map unique values to an object's keys, adding to existing keys every time the same value is encountered.
+- Use `Object.entries()` on the result in combination with `Array.prototype.reduce()` to get the most frequent value in the array.
+
+```js
+const mostFrequent = arr =>
+  Object.entries(
+    arr.reduce((a, v) => {
+      a[v] = a[v] ? a[v] + 1 : 1;
+      return a;
+    }, {})
+  ).reduce((a, v) => (v[1] >= a[1] ? v : a), [null, 0])[0];
+```
+
+```js
+mostFrequent(['a', 'b', 'a', 'c', 'a', 'a', 'b']); // 'a'
+```