22 lines
563 B
Markdown
22 lines
563 B
Markdown
---
|
|
title: Check if array has duplicates
|
|
tags: array
|
|
cover: umbrellas
|
|
firstSeen: 2020-10-22T20:23:09+03:00
|
|
lastUpdated: 2020-10-22T20:23:09+03:00
|
|
---
|
|
|
|
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
|
|
```
|