16 lines
377 B
Markdown
16 lines
377 B
Markdown
---
|
|
title: countOccurrences
|
|
tags: array,intermediate
|
|
---
|
|
|
|
Counts the occurrences of a value in an array.
|
|
|
|
Use `Array.prototype.reduce()` to increment a counter each time you encounter the specific value inside the array.
|
|
|
|
```js
|
|
const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);
|
|
```
|
|
|
|
```js
|
|
countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3
|
|
``` |