Count occurrences of value in array with reduce

Doesn't require creation of new array as with current solution.

snippets/count-occurrences-of-a-value-in-array.md

@@ -5,3 +5,9 @@ Use `filter()` to create an array containing only the items with the specified v
 ```js
 var countOccurrences = (arr, value) => arr.filter(v => v === value).length;
 ```
+
+Use reduce() to increment a counter each time you encounter the specific value; does not create new array like filter().
+
+```js
+var countOccurrences = (arr, value) => arr.reduce((a, v) => v===value ? a + 1 : a + 0, 0);
+```